A prefix attaches to the front of an existing word and modifies its meaning without changing its part of speech: hacer (to do) → deshacer (to undo), posible (possible) → imposible (impossible), guerra (war) → posguerra (post-war). Spanish has roughly thirty productive prefixes, all of them inherited from Latin (with a handful from Greek), and most of them transparent to an English speaker because the same prefixes are alive in English from the same Latin source.
This page covers the prefixes you will actually meet in modern peninsular Spanish, grouped by what they do: negation, space and time, quantity, intensification, and verb-forming (Aktionsart). Knowing the prefixes turns thousands of unfamiliar words into self-explanatory ones — antibélico is recognisably "anti-war", predeterminar is "to pre-determine", retroalimentación is "feedback" (literally "retro-feeding"). Two crucial points before we start: prefixes do not change the gender or word class of the base (una posibilidad → una imposibilidad, both feminine), and prefixes never carry the main stress, so the stress pattern of the base word is preserved.
Negation and opposition: in- / im- / i-
The Latinate negation prefix that converts an adjective into its opposite — the direct equivalent of English in- / im- / il- / ir-. The form depends on what follows: im- before p or b, i- before l or r, in- elsewhere.
Es imposible reservar mesa en ese restaurante un viernes sin llamar con tres días de antelación.
It's impossible to book a table at that restaurant on a Friday without calling three days ahead.
Lo que hizo fue completamente ilegal y, además, irracional.
What he did was completely illegal and, on top of that, irrational.
The alternation is purely phonological — Spanish is uncomfortable with nl- and nr- clusters and resolves them by assimilating n to the following sound. Common pairs: posible → imposible, paciente → impaciente, probable → improbable, propio → impropio; legal → ilegal, legible → ilegible, lógico → ilógico; racional → irracional, real → irreal, responsable → irresponsable; capaz → incapaz, necesario → innecesario, correcto → incorrecto, moral → inmoral, seguro → inseguro.
Negation and reversal: des-
The native Spanish negation and reversal prefix — broadly equivalent to English un- or dis-. It is far more productive than in- and attaches freely to verbs, nouns, and adjectives. With verbs it generally signals reversal (undoing an action); with nouns and adjectives it generally signals absence or negation.
He tenido que deshacer la maleta dos veces porque me había olvidado el cargador del móvil.
I've had to unpack my suitcase twice because I'd forgotten my phone charger.
La habitación está totalmente desordenada — voy a tardar una hora en recogerla.
The room is completely messy — it's going to take me an hour to tidy it up.
Verb pairs (reversal): hacer → deshacer (undo), atar → desatar (untie), vestir → desvestir (undress), montar → desmontar (dismantle), aparecer → desaparecer (disappear), conectar → desconectar (disconnect), cargar → descargar (unload, download), bloquear → desbloquear (unblock). Adjective/noun pairs (negation): honesto → deshonesto (dishonest), ordenado → desordenado (messy), cuidado → descuido (carelessness), empleo → desempleo (unemployment), acuerdo → desacuerdo (disagreement), conocido → desconocido (unknown).
Opposition: anti- and contra-
Anti- is the Greek-origin prefix for "against" — used the same way as in English (antiviral, antibiótico, antimonárquico). Contra- is the Latin equivalent and is also productive, especially with verbs and nouns of action.
La nueva crema antiarrugas no funciona ni la mitad de bien que dice la publicidad.
The new anti-wrinkle cream doesn't work even half as well as the advertising claims.
El gobierno ha anunciado una contraoferta que los sindicatos ya han rechazado.
The government has announced a counter-offer that the unions have already rejected.
Common anti- words: antibiótico, antivirus, antimonárquico, antifascista, antitabaco, antiarrugas, antiestrés, antirrobo, antinatural. Common contra- words: contraataque (counter-attack), contraoferta (counter-offer), contraseña (password), contradecir (to contradict), contraindicación (contraindication), contrarreloj (against the clock — used as a noun for a time-trial in cycling). Note the doubled r when contra- meets a root starting with r: contrarreloj, contrarrevolución.
Time and space: ante-, pre-, pos-, re-, retro-
These are the spatial-temporal prefixes that mark "before", "after", "again", and "backward". Ante- and pre- both mean "before" but distribute differently: ante- tends to attach to nouns of time and place (anteayer, antesala); pre- attaches to verbs and adjectives of action (predecir, prejuicio, precaución).
Anteayer fui al médico y aún no me ha llegado el resultado del análisis.
The day before yesterday I went to the doctor and the test result still hasn't arrived.
Te recomiendo reservar el AVE con antelación; los precios suben mucho la víspera.
I'd recommend booking the AVE in advance; the prices go up a lot the day before.
Pos- (or post- in formal writing) marks "after": posguerra (post-war period), posmoderno (postmodern), posventa (after-sales). The modern Spanish spelling tendency is without the t: the RAE recommends posguerra, posmoderno, posdata over postguerra, postmoderno, postdata — though both spellings are accepted.
La novela retrata la España de la posguerra desde la mirada de un niño de diez años.
The novel depicts post-war Spain from the perspective of a ten-year-old child.
Re- has two distinct uses. Its productive prefix meaning is "again": hacer → rehacer (to redo), leer → releer (to reread), escribir → reescribir (to rewrite), abrir → reabrir (to reopen), cargar → recargar (to recharge), aparecer → reaparecer (to reappear), iniciar → reiniciar (to restart). Its colloquial peninsular use is as an intensifier in informal speech: rebueno (really good), rerico (delicious), requeteguapo (totally gorgeous — with the playful reduplication requete-).
He tenido que rehacer el trabajo entero porque el profesor lo encontró rebuenísimo pero mal estructurado.
I had to redo the whole essay because the teacher found it really excellent but badly structured.
Retro- means "backward, going back": retroceder (to go back), retrovisor (rear-view mirror), retroalimentación (feedback), retrospectivo (retrospective).
Position and degree: sub-, super-
Sub- means "under, below" — both spatially and figuratively: subterráneo (underground), submarino (submarine), subdesarrollado (underdeveloped), subestimar (to underestimate), subtítulo (subtitle). Super- means "above, beyond" and is doubly useful in Spanish because it appears both as a formal/scientific prefix and as a colloquial intensifier.
Voy un momento al supermercado a comprar algo para la cena.
I'm popping over to the supermarket to buy something for dinner.
El concierto estuvo superchulo — los del grupo se quedaron luego a firmar discos.
The concert was super cool — the band members stayed afterwards to sign records.
The colloquial super- attaches to almost any adjective in informal peninsular speech: superbueno (really good), superchulo (super cool), superdifícil (super hard), superrápido (super fast). Written as one word with the adjective; the RAE accepts both super (standalone adverb) and super- (joined prefix), though the joined form is more common in print.
Quantity prefixes: bi-, tri-, multi-, mono-
The numeral prefixes inherited from Latin and Greek. Bi- (two), tri- (three), cuatri- / tetra- (four), quint- / penta- (five), multi- (many, Latin), poli- (many, Greek), mono- (one, Greek).
Mi sobrino es bilingüe desde los tres años — habla castellano con la madre e inglés con el padre.
My nephew has been bilingual since age three — he speaks Spanish with his mother and English with his father.
Trabaja para una multinacional con sede en Frankfurt pero oficinas en doce países.
She works for a multinational based in Frankfurt but with offices in twelve countries.
Examples: bilingüe (bilingual), bimestral (bimonthly), bipolar (bipolar), trilingüe (trilingual), triángulo (triangle), triciclo (tricycle), multicolor (multicoloured), multimillonario (multi-millionaire), multinacional (multinational), multitarea (multitasking), monolingüe (monolingual), monopatín (skateboard, peninsular), monólogo (monologue), poliédrico (polyhedral), poliglota (polyglot), politeísta (polytheistic). Note the ü in bilingüe / trilingüe / monolingüe / pingüino — the diaeresis is mandatory and tells the reader the u is pronounced rather than silent.
Intensifier prefixes: archi-, hiper-, mega-, extra-, ultra-
A family of prefixes for "very, extremely, beyond". Archi- is the most learned and is somewhat literary; hiper- and mega- are colloquial and very common in youth speech; extra- is neutral; ultra- tilts political (it often appears in ultraderecha, ultrasur).
Es un actor archifamoso en su país, pero aquí nadie sabe quién es.
He's a hugely famous actor in his country, but here nobody knows who he is.
El centro comercial nuevo es hipergrande — necesitas el mapa para encontrar la salida.
The new shopping centre is enormous — you need the map to find the exit.
Examples: archifamoso (very famous), archiconocido (extremely well-known), hipermercado (hypermarket — bigger than a supermarket), hiperactivo (hyperactive), megaproyecto (mega-project), megaconcierto (huge concert), extraordinario (extraordinary), extracurricular (extra-curricular), ultravioleta (ultraviolet), ultraderecha (far right), ultrasonido (ultrasound).
Aktionsart prefixes: a- and en- / em-
These prefixes do something distinctive — they turn nouns and adjectives into verbs of "becoming" or "putting into a state". A- tends to attach to adjectives and produce verbs of approaching or causing the state (claro → aclarar "to clarify", cerca → acercar "to bring close"). En- / em- (with the same m-before-p/b rule as in-) tends to produce verbs of "putting into" or "becoming" (rojo → enrojecer "to redden, blush", botella → embotellar "to bottle, to put into bottles").
Cuando le pregunté por su novio nuevo, se puso a enrojecer y cambió de tema enseguida.
When I asked her about her new boyfriend, she started blushing and changed the subject straight away.
Acércate un poco más, que no te oigo bien con todo este ruido.
Come a bit closer, I can't hear you well with all this noise.
This pattern is technically parasynthesis — the prefix and the verb-forming suffix (-ar or -ecer) attach simultaneously, because neither *acerca nor *cercar (in this sense) exists as a separate stage. See Parasíntesis y formación inversa for the deeper treatment. Common pairs: cerca → acercar (bring close), claro → aclarar (clarify), cobarde → acobardar (cow, intimidate), largo → alargar (lengthen), corto → acortar (shorten); rojo → enrojecer (redden), triste → entristecer (sadden), vejez → envejecer (age, get old), noble → ennoblecer (ennoble), grande → engrandecer (enlarge), pobre → empobrecer (impoverish).
How prefixes combine — stress and accents
Prefixes never carry the main stress of the word. The base keeps its stress and its accent: posible (stress on si) → imposible (stress still on si); político (antepenultimate stress) → apolítico (still antepenultimate stress within the base). When the base already has a written accent, the accent stays in place so long as the stress doesn't move: árbol → subárbol, íntimo → preíntimo. (Don't confuse this with cases where a verb-forming suffix is also added — límite → delimitar drops the accent because the stress now falls on the final -ar, not because of the prefix.)
Hyphenation with prefixes is rare in Spanish. The RAE convention is to write the prefix joined to the base without a hyphen in nearly all cases: posguerra, antiarrugas, supermercado, multinacional. The exceptions are: (1) when the base is a proper noun or an acronym (anti-OTAN, pro-ETA), (2) when the prefix is followed by a number (sub-21, pre-1492), and (3) for clarity in coined or one-off combinations.
Common mistakes
❌ Inposible saber qué va a pasar mañana.
The negation prefix assimilates: in- becomes im- before p or b. The form is imposible, not inposible.
✅ Imposible saber qué va a pasar mañana.
Impossible to know what's going to happen tomorrow.
❌ Voy a unhacer la maleta.
Calque from English 'undo'. Spanish does not use a Spanish-English hybrid; the productive native reversal prefix is des-.
✅ Voy a deshacer la maleta.
I'm going to unpack the suitcase. — des- is the productive reversal prefix in Spanish.
❌ Mi hija es bi-lingüe desde pequeña.
Spanish does not hyphenate prefixes with common nouns. Write the prefix joined to the base: bilingüe.
✅ Mi hija es bilingüe desde pequeña.
My daughter has been bilingual since she was little.
❌ Hacer feliz a alguien es muy difícil — pero hacerle infeliz es también difícil.
Infeliz is grammatically possible but stylistically marked — Spanish prefers triste, desdichado, or no muy feliz. The Latinate in- doesn't combine freely with native-stock adjectives.
✅ Hacer feliz a alguien es muy difícil — pero hacerle triste es también difícil.
Making someone happy is very hard — but making them sad is also hard. — triste is the natural opposite of feliz, not infeliz.
❌ Es un actor muy archi-famoso en Argentina.
No hyphen with the prefix archi-. Written as one word: archifamoso. Same rule for hiper-, super-, multi- when joined to a common adjective or noun.
✅ Es un actor archifamoso en Argentina.
He's a hugely famous actor in Argentina.
Key takeaways
- Prefixes attach to the front of a word, never change the gender or the word class, and never carry the main stress.
- Negation: in- / im- / i- (Latinate, attaches to Latinate adjectives), des- (native, attaches to verbs for reversal and to nouns/adjectives for absence), anti- and contra- (against).
- Time and space: ante- and pre- (before), pos- (after, modern peninsular without t), re- (again — and colloquial intensifier), retro- (backward), sub- (under), super- (above, also colloquial intensifier).
- Quantity: bi-, tri-, multi-, mono-, poli-. Watch for the diaeresis in bilingüe, trilingüe.
- Intensifiers (often colloquial): archi-, hiper-, mega-, extra-, ultra-, plus colloquial super- and re-.
- Aktionsart: a-
- adjective + -ar / -ecer, en- / em-
- adjective + -ar / -ecer (parasynthesis). These create verbs of becoming or causing a state from adjectives and nouns.
- adjective + -ar / -ecer, en- / em-
- Prefixes are written joined to the base in standard Spanish, no hyphen, except with proper nouns, acronyms, and numbers.
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