Mentir (To Lie) — Full Conjugation

Mentir means to tell a lie — and nothing else. This is important, because English speakers routinely reach for mentir when they want to say deceive, trick, or mislead. Those verbs in Portuguese are enganar (to deceive, to fool), not mentir. A salesman who tricks you about the price is a enganar-te; a child who insists they did not eat the biscuit when they did is a mentir. The distinction matters: mentir is specifically about saying something that you know is false. It is a speech act.

Mentir is a third-conjugation (-ir) verb with the characteristic Portuguese e → i stem change that you also see in sentir, preferir, ferir, divertir, and others. The change shows up in the eu form of the present indicative (minto) and throughout the present subjunctive (minta, mintas…). Outside of those, the vowel stays e: mentes, mente, mentimos; menti, mentiste, mentiu; mentiria. Learn the stem-change pattern once and you have it for every verb in this group.

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Present indicative — presente do indicativo

The eu form is minto (not mento). Every other form uses e.

Imperfect indicative — pretérito imperfeito

Regular; built on the stem menti-.

Preterite indicative — pretérito perfeito simples

Regular throughout. No stem change in this tense.

Pluperfect indicative, simple — pretérito mais-que-perfeito simples

Literary; everyday speech uses the compound.

Pluperfect indicative, compound — pretérito mais-que-perfeito composto

Present perfect — pretérito perfeito composto

Repeated or continuous action up to now. Tens mentido muito ultimamente — you have been lying a lot lately.

Simple future — futuro do indicativo simples

Future perfect — futuro perfeito

Conditional — condicional (futuro do pretérito)

Conditional perfect — condicional composto

Present subjunctive — presente do conjuntivo

Built from the eu form minto. Every form carries the i.

Imperfect subjunctive — imperfeito do conjuntivo

Regular.

Future subjunctive — futuro do conjuntivo

Regular.

Present perfect subjunctive — pretérito perfeito do conjuntivo

Pluperfect subjunctive — pretérito mais-que-perfeito do conjuntivo

Future perfect subjunctive — futuro perfeito do conjuntivo

Imperative — imperativo

Affirmative:

Negative (subjunctive with não):

In reality you will hear não mintas! ("don't lie!") far more than mente! — for obvious pragmatic reasons, positive commands to lie are rare. The negative imperative is a staple of parenting and arguments alike.

Personal infinitive — infinitivo pessoal

Compound personal infinitive — infinitivo pessoal composto

Usage notes

Mentir is intransitive or takes an indirect object introduced by a: you lie to someone. You cannot lie something in the way you say something in English — there is no direct object of the thing lied about. Instead, use sobre or acerca de for the topic, or restructure with dizer mentiras (tell lies) or mentir sobre (lie about).

• mentir (absolute) — to lie, to be a liar
• mentir a alguém — to lie to someone
• mentir sobre algo — to lie about something
• dizer uma mentira / dizer mentiras — to tell a lie / to tell lies
• apanhar alguém na mentira — to catch someone in a lie

Mentir vs. enganar — the distinction that trips English speakers

Mentir is about saying something false on purpose. Enganar is about deceiving, tricking, misleading — it can be done without a single spoken word. A used-car salesman who hides a crack in the engine block is a enganar-te (deceiving you), even if he never opens his mouth. A child who says "I wasn't playing with your phone" when they were is a mentir (lying).

Do not use mentir for "cheat on an exam" (that's copiar or fazer batota), for "cheat on a partner" (that's trair or the more colloquial pôr cornos), or for "mislead" in a general sense (that's enganar or induzir em erro).

Opposite: dizer a verdade / diga-me a verdade

The natural antonym of mentir is the fixed expression dizer a verdade. In commands, diga-me a verdade (formal) or diz-me a verdade (informal) — tell me the truth.

Example sentences in context

Common mistakes

Key takeaways

• Mentir means only to tell a lie — a spoken or written false claim made knowingly. It is not the same as enganar (to deceive, to fool).
• The verb has the e → i stem change in the eu-form of the present (minto) and throughout the present subjunctive (minta, mintas, mintamos, mintam). Everywhere else the stem is menti-.
• Mentir takes an indirect object with a (mentir a alguém), not a direct object.
• Pair it with sobre or acerca de to express the topic of the lie: mentir sobre algo.
• The negative imperative (não mintas!) is far more common than the affirmative — which is as it should be.
• For "cheat" (an exam, a partner), reach for fazer batota / copiar or trair, not mentir.