oir

Oir is a term used in French linguistics to denote the class of verbs whose infinitives end in -oir. In traditional grammar, these verbs form the groupe oir, a set of irregular or semi-regular verbs that share certain stem alternations and endings across tenses. They are distinct from the more regular -er and -re verb groups and from the -ir verbs, and they include several of the most commonly used French verbs.

The oir group includes verbs such as boire (to drink), voir (to see), devoir (to have to), pouvoir (to be able), recevoir (to receive), savoir (to know), croire (to believe), and pleuvoir (to rain). These verbs exhibit irregular present-tense stems and irregular past-participle forms. For example, present tense forms include je bois, tu bois, il boit, nous buvons, vous buvez, ils boivent for boire; je vois, tu vois, il voit, nous voyons, vous voyez, ils voient for voir; je dois, tu dois, il doit, nous devons, vous devez, ils doivent for devoir; and je peux, tu peux, il peut, nous pouvons, vous pouvez, ils peuvent for pouvoir. Past participles vary as bien: bu for boire, vu for voir, dû for devoir, pu for pouvoir, reçu for recevoir, su for savoir, cru for croire, plu for pleuvoir.

The groupe oir is characterized by a mix of stem changes and endings that require individual memorization for each verb. Despite irregularities, the oir verbs remain a core component of everyday French, with frequent use across speaking and writing. The suffix -oir thus represents a distinctive and historic branch of French verb conjugation.