Sem means without. It is the exact mirror image of com (with) — wherever com adds something, sem takes it away. The good news for learners: sem is mechanically simpler than com. It does not contract with articles, and — crucially — it does not fuse with pronouns. Where com forces you into comigo and conosco, sem just sits next to the ordinary prepositional pronouns: sem mim, sem nós. The two interesting features of sem are syntactic, not phonetic: sem + infinitive translates English "without -ing," and sem que triggers the subjunctive.
Absence — "without" a thing
The core use: marking something missing or excluded. Coffee without sugar, a house without a roof, a day without rain.
Eu tomo o café sem açúcar, obrigado.
I take my coffee without sugar, thanks.
Saí de casa sem guarda-chuva e me arrependi.
I left home without an umbrella and regretted it.
Um mundo sem música seria muito triste.
A world without music would be very sad.
Sem with pronouns — no fusion
This is the headline contrast with com. While com mutates into comigo, contigo, conosco, the preposition sem does nothing of the kind. It takes the plain oblique (prepositional) pronouns: mim, ti, ele/ela, nós, vocês.
| with (com) | without (sem) | meaning |
|---|---|---|
| comigo | sem mim | without me |
| contigo | sem ti (regional) | without you (informal) |
| com você | sem você | without you |
| conosco | sem nós | without us |
Eles foram ao cinema sem mim.
They went to the movies without me.
Não consigo fazer isso sem você.
I can't do this without you.
Sem + infinitive — English "without -ing"
When English chains without to an -ing verb ("he left without saying anything"), Portuguese uses sem + the infinitive. There is no gerund here — the infinitive is the correct, default choice.
Ela saiu sem falar com ninguém.
She left without speaking to anyone.
Ele entrou sem bater na porta.
He came in without knocking on the door.
Passei a noite inteira sem dormir.
I spent the whole night without sleeping.
A subtle but powerful upgrade: because Portuguese has a personal infinitive (an infinitive that carries person endings), you can make the implied subject explicit when it differs. Sem eles saberem = "without them knowing." For now, know that sem dormir / sem falar (plain infinitive) is what you'll use most.
Sem que + subjunctive
When the "without" clause has its own subject and a finite verb, you switch from sem + infinitive to the conjunction sem que, and sem que always takes the subjunctive. The logic is the same logic that governs the subjunctive everywhere: the action after sem que is not presented as a fact — it's the thing that did not or should not happen, hovering in the realm of the non-real.
Ele saiu sem que ninguém o visse.
He left without anyone seeing him.
Consegui terminar tudo sem que você precisasse ajudar.
I managed to finish everything without you needing to help.
Ela arrumou a surpresa sem que ele desconfiasse de nada.
She set up the surprise without him suspecting anything.
Notice the choice point: if the two clauses share the same subject, prefer sem + infinitive (saí sem falar). If the second clause has a different subject, use sem que + subjunctive (saí sem que ele percebesse). For the wider family of subjunctive-triggering conjunctions, see the subjunctive with conjunctions page.
Sem as the opposite of com — useful pairs
Because sem and com are antonyms, they pair up neatly. Recognizing the pairs helps both stick.
Prefiro a pizza sem cebola, mas com bastante queijo.
I prefer the pizza without onion, but with lots of cheese.
Ele falou sem medo, com toda a calma do mundo.
He spoke without fear, with all the calm in the world.
Note that sem also feeds the same kind of state expressions as com: estar sem dinheiro (to be broke), estar sem tempo (to have no time), ficar sem palavras (to be left speechless).
Common Mistakes
❌ Eles viajaram sem migo.
Incorrect — 'sem' does not fuse; the form is 'sem mim'.
✅ Eles viajaram sem mim.
They travelled without me.
❌ Ela saiu sem falando com ninguém.
Incorrect — 'sem' takes the infinitive, not the gerund.
✅ Ela saiu sem falar com ninguém.
She left without speaking to anyone.
❌ Ele entrou sem que ninguém viu.
Incorrect — 'sem que' requires the subjunctive (visse), not the indicative.
✅ Ele entrou sem que ninguém visse.
He came in without anyone seeing.
❌ Tomo o café sem do açúcar.
Incorrect — 'sem' takes the noun directly; no 'de'.
✅ Tomo o café sem açúcar.
I take my coffee without sugar.
❌ Não consigo fazer isso sem que você.
Incorrect — with no verb, use plain 'sem você', not 'sem que'.
✅ Não consigo fazer isso sem você.
I can't do this without you.
Key Takeaways
- sem = without; it is the antonym of com and mechanically simpler.
- sem does not fuse with pronouns: sem mim, sem ti, sem nós — never any "semmigo."
- sem + infinitive translates English "without -ing" (sem falar = without speaking).
- sem que + subjunctive is required when the clause has its own, different subject.
- It does not contract with articles: sem o dinheiro, sem a chave stay as two words.
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Start learning Portuguese→Related Topics
- Preposition 'Com': WithA1 — How 'com' marks accompaniment, instrument, and manner — plus the fused pronoun forms comigo, contigo, conosco and the 'com + noun = adverb' pattern.
- Subjunctive with Triggering ConjunctionsB1 — Conjunctions like para que, antes que, embora, and caso that always force the subjunctive in Brazilian Portuguese.
- Personal Pronouns After PrepositionsA2 — The tonic pronoun set used after prepositions — mim, ti, ele, nós — plus the special fusions comigo and contigo.
- Prepositions: OverviewA1 — A map of the Brazilian Portuguese preposition system, the obligatory contractions with articles and pronouns, and why prepositions almost never map one-to-one to English.