Cair (To Fall) — Full Conjugation

Cair means to fall — physically (to drop, to tumble), metaphorically (to fall out of favor, to fall into despair), and idiomatically (cair bem, cair em desgraça). It belongs to a small but important class of verbs in -air (alongside sair to leave and trair to betray) whose conjugation is largely regular but introduces one striking orthographic feature: the hiatus accent. Whenever the verb ending puts the stressed i in hiatus with the preceding a (that is, the two vowels form separate syllables rather than a diphthong), the i takes an acute accent: caímos, caí, caíste, caído.

This hiatus accent is not optional, and it is not cosmetic — it is part of the spelling. Miss it, and you have misspelled the word. This page walks through every form so you can see exactly where the accent belongs and why.

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Present indicative — presente do indicativo

Note the 1sg caio (with -io, like saio, traio) and the nós form caímos with an acute accent on the í.

Why the accent in caímos? Because the stress falls on -í-, and the í is in hiatus with the preceding a. Without the accent (caimos), the pronunciation would default to the diphthong ai, giving you a different word. In caem and cai, the stress is on a, not on i — no accent.

Imperfect indicative — pretérito imperfeito

All imperfect forms of cair carry the hiatus accent on -í-: caía, caías, caía, caíamos, caíeis, caíam.

Preterite indicative — pretérito perfeito simples

Same logic: hiatus accent whenever í is stressed and separate from a.

The 3sg caiu has no accent because the stress falls on -iu as a diphthong; the 3pl caíram has an accent because í is stressed and in hiatus. Note: the 1pl caímos is identical in present and preterite — context disambiguates.

One of the most important distinctions for learners: cai (3sg present, "he/she falls") versus caí (1sg preterite, "I fell"). Same letters, different accent, different meaning.

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

All forms take the hiatus accent. The 3pl caíram is identical to the preterite.

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

The everyday way to say had fallen. Formed with the imperfect of ter plus the past participle caído (also with hiatus accent).

Present perfect — pretérito perfeito composto

Describes repeated or continuous action up to the present. Tenho caído muito em bicicleta ultimamente = I've been falling off my bike a lot lately.

Simple future — futuro do indicativo simples

Regular, built on the infinitive. No hiatus accent needed because the stress is on the endings.

Future perfect — futuro perfeito

Conditional — condicional (futuro do pretérito)

Conditional perfect — condicional composto

Present subjunctive — presente do conjuntivo

Built on the 1sg stem cai- plus the -a endings characteristic of the subjunctive of -er/-ir verbs.

In the subjunctive, the stress falls on the a, not the i — so no hiatus accent. Caia (2 syllables: cai-a), stressed on cai.

Imperfect subjunctive — imperfeito do conjuntivo

Built on the preterite stem with hiatus accent.

Future subjunctive — futuro do conjuntivo

Built on the infinitive. Because stress is on -ir, no hiatus accent needed.

Note the hiatus accents in caíres and caírem (stress on í, separate from a), but no accent in cair, cairmos, cairdes (stress on the ending).

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:

Cuidado, não caias! = Careful, don't fall!

Personal infinitive — infinitivo pessoal

Identical in form to the future subjunctive; hiatus accent when í is stressed in hiatus.

Compound personal infinitive — infinitivo pessoal composto

The all-important accent distinction: cai vs caí

This is the single most common error for learners:

• cai — 3sg present indicative (ele cai = he falls) or 2sg affirmative imperative (cai! = fall!)
• caí — 1sg preterite indicative (eu caí = I fell)

Both are pronounced identically in isolation — the spelling (and the accent) carries the grammatical meaning. Miss the accent and you change the tense.

Common uses and collocations

• cair no chão — to fall on the ground
• cair de cansaço — to be dead tired (literally, "to fall from tiredness"; idiom)
• cair em desgraça — to fall from grace, to fall out of favor
• cair em si — to come to one's senses, to realize one's mistake
• cair nas mãos de alguém — to fall into someone's hands
• cair de boca — to fall face-first
• cair bem / cair mal — to sit well / badly with someone (either literally, of food, or figuratively, of a comment or gift). Essa comida cai-me mal = that food doesn't agree with me. O comentário caiu mal = the comment went down badly.
• cair a ficha — literally for the coin to drop (of a phone); figuratively, to finally understand something. Só agora me caiu a ficha = it's only now sinking in.
• cair na asneira / cair na tentação — to fall into stupidity / into temptation
• cair como um patinho — to be gullible (literally "to fall like a little duck")

Example sentences in context

Common mistakes

Key takeaways

• Cair is regular in structure but requires the hiatus accent (á, é, í, ó, ú) wherever the stressed -í- forms a separate syllable from a preceding a.
• Crucial distinction: cai (3sg present, "he falls") versus caí (1sg preterite, "I fell") — identical letters, the accent carries the grammar.
• 1sg present is caio (not caiu, which is 3sg preterite), following the pattern of sair → saio.
• The past participle is caído with a hiatus accent — always write it.
• Cair bem / cair mal is a high-frequency idiom with distinct meanings for clothes (to suit / not suit), food (to agree / not agree with one), and comments (to go down well / badly).
• The -air class includes cair, sair, trair, atrair, distrair, subtrair — all follow the same hiatus-accent pattern.