Defective Verbs

A defective verb (verbo defectivo) is one whose conjugation paradigm has gaps — specific persons, tenses or moods that either do not exist, are systematically avoided, or are replaced with a periphrasis. This is categorically different from an irregular verb. An irregular verb like ser or fazer has all its forms; they just do not follow the regular endings. A defective verb lacks forms altogether. If you try to say the missing form, a native speaker will hesitate, laugh, or quietly rephrase you — because there is simply no word there to say.

Defectiveness in Portuguese is not a random list to be memorised. It almost always has a linguistic cause. Knowing the cause tells you which forms will be missing and what to say instead. The two drivers are phonological taboo (the missing form would sound identical to a stigmatised word or would be awkward to pronounce) and semantic incompatibility (the verb's meaning cannot be predicated of a first-person speaker, so the form has no real-world use and never stabilised).

This page covers the six most important defective verbs in modern European Portuguese: falir, abolir, colorir, precaver-se, reaver, feder. For each, you will see exactly which forms exist, which do not, and the periphrasis that real speakers reach for instead.

Defective vs. irregular — make sure the distinction is clean

Before diving in, it is worth contrasting the two categories with a concrete pair:

The two causes of defectiveness

1. Phonological avoidance

Some forms are missing because they would be homophonous with another word — sometimes a vulgar one, sometimes just an unfortunate collision — or because the resulting consonant cluster is phonetically awkward. Portuguese is conservative about avoiding these: rather than tolerate the homophone, the language simply leaves the slot empty. Falir, feder, colorir are all affected this way, with falir's missing falo (homophonous with the noun falo, "phallus") being the textbook example. This type of defectiveness is sometimes called defectividade por tabu.

2. Semantic incompatibility

Other verbs are defective because their meaning makes little sense in certain persons. Weather verbs like chover (to rain) are the clearest case — eu chovo ("I rain") is nonsensical, so the 1sg form simply does not exist in natural use. Reflexive precaver-se falls in an intermediate zone: it has a semantic argument structure that historically blocked some forms, leaving a paradigm with only two surviving present-tense forms.

The payoff of understanding these causes: once you know why a form is missing, you rarely need to memorise the gap. You just rephrase.

Falir — to go bankrupt

Falir is the headline example of a phonologically defective verb. The missing 1sg present indicative (the historically expected form would be falo) collides with the Portuguese noun falo (phallus). Rather than tolerate the homonymy, the language refuses the form, and the entire present subjunctive goes with it — because the subjunctive stem is built from the 1sg indicative stem.

What exists and what does not

The rule of thumb is: any form where the stem is unstressed is fine (falimos, falíamos, falirei); any form where the stem would be stressed in the present is missing.

What to say instead

Speakers reach for ir à falência (to go bankrupt, literally "to go to bankruptcy") or the periphrastic ir + infinitive (vou falir "I'm going to go bankrupt"), both of which are completely natural and avoid the missing finite forms, because the infinitive falir itself is perfectly grammatical.

Notice the self-correction in the last example: the speaker starts to produce a 3pl form (which technically exists as falem — but is so rarely used that even natives reroute mid-sentence) and rephrases.

Abolir — to abolish

Abolir is semantically perfect for a first-person subject (I abolish the old rule), but the 1sg form abolo is systematically avoided because of a historical taboo association — and because modern ears simply do not expect to hear it. The entire present subjunctive is consequently also gone. Unlike falir, though, the 2sg, 3sg and 3pl present forms (aboles, abole, abolem) are completely fine and are used routinely.

All other tenses (imperfect, preterite, future, conditional, imperfect and future subjunctive, personal infinitive, gerund, participle) are complete and regular.

What to say instead

For the missing 1sg, use the periphrasis vou abolir (I'm going to abolish) or rephrase with a different verb such as acabar com (to put an end to) or eliminar (to eliminate).

Colorir — to color

Colorir patterns exactly like abolir: the 1sg present indicative and the whole present subjunctive are missing; 2sg/3sg/3pl (colores, colore, colorem) work fine. Here the motivation is phonological awkwardness plus the fact that a competing verb (pintar) covers the meaning so well that speakers never had pressure to fill the gap.

What to say instead

Speakers reach for pintar (to paint), dar cor a (to give colour to), or just the periphrasis vou colorir / estou a colorir.

Precaver-se — to take precaution

Precaver-se is the most radically defective verb on this page. Historically analysed as a compound of pre- + ver + reflexive, but it stopped inheriting most of ver's forms centuries ago. Today only two present indicative forms survive, and those forms are themselves rare in everyday speech: precavemo-nos (1pl) and precaveis-vos (2pl, already archaic because vós itself is archaic). Crucially, the paradigm is not just ver's paradigm with pre- in front — you cannot say *precavejo-me or *precaveja-me the way you say vejo, veja for ver.

What exists

What to say instead

Speakers use prevenir-se (to protect oneself, to take precaution) or ter cuidado com (to be careful with). Prevenir-se is fully regular and completely fills the gap.

Reaver — to recover, to get back

Reaver is a fascinating semi-defective verb that survives mainly in administrative and legal contexts. It is historically re- + haver, and it inherits its paradigm from haver — but only in those forms where haver retains its -v- stem. Wherever haver's conjugation drops the -v- (as in 1sg hei, 3sg há, preterite houve), reaver has no form at all.

What exists

Note the preterite: reouve, reouveste, reouve, reouvemos, reouvestes, reouveram — built directly on houve. The present subjunctive is missing entirely: haver's subjunctive (haja, hajas...) drops the -v-, so there is no -v- stem for reaver to inherit, and the slot is left empty. The future and conditional are complete and regular (reaverei, reaveria), because those endings attach to the full infinitive reaver.

What to say instead

Recuperar (to recover, to get back) is the go-to replacement. It is fully regular and semantically equivalent in almost every context. Reaver survives mainly in legal writing (reaver bens, to recover assets) and in slightly formal register.

Feder — to stink

Feder is the borderline case and the one where usage has shifted most over the last century. Traditionally the 1sg present indicative was avoided: fedo was considered both phonetically awkward and too close for comfort to certain vulgar items. Classical grammars treat it as defective. In modern informal speech, however, you will hear eu fedo without much difficulty — the taboo has weakened. In careful or formal usage, the form is still generally avoided.

Current status

For formal writing, prefer cheirar mal (to smell bad) or estar a cheirar mal. In conversation, feder is unproblematic in non-1sg forms.

PT-PT vs. Brazilian Portuguese differences

Defectiveness patterns are broadly shared between the two varieties, but there are three practical differences:

1. Precaver-se survives slightly longer in BP administrative writing; in PT-PT it is almost entirely replaced by prevenir-se outside legal contexts.
2. Reaver is more commonly encountered in BP legal language than in PT-PT, where recuperar has spread further even into formal usage.
3. Feder's taboo on 1sg fedo is weaker in BP informal speech; some grammarians describe it as "not defective in modern BP." PT-PT retains more of the classical avoidance.

Weather verbs and true impersonals

A brief word on the related category of impersonal verbs — verbs like chover (to rain), nevar (to snow), trovejar (to thunder). These are defective by semantic necessity: only the 3sg form occurs in natural speech, because the subject is always understood to be "the sky" or "the weather." They are covered separately in impersonal constructions complete, because they pattern with a larger class and are not usually counted as "defective" in the narrow sense used on this page.

Common mistakes

Key takeaways

• Defective verbs have missing forms, not just irregular ones. Trying to produce the missing form is not "a mistake" in the usual sense — the form literally does not exist.
• The two causes are phonological/taboo avoidance (falir, colorir, feder) and historical/semantic fossilisation (precaver-se, reaver).
• For every defective verb, speakers use a periphrasis or a synonymous non-defective verb. Learning the workaround is more important than memorising the gap.
• The pattern "1sg missing → present subjunctive missing" holds in almost every case, because the subjunctive stem is built from the 1sg indicative stem. If one is gone, the other is too.
• Most defective verbs still have a full imperfect, preterite, future, conditional, imperfect and future subjunctive, and personal infinitive. The gaps are concentrated in the present indicative and subjunctive.

For a searchable alphabetical list with one-line usage notes per verb, see defective verb list. For the closely related category of weather and other impersonal verbs, see impersonal constructions complete.