What is the meaning of -ir?

forms infinitives

forms the infinitives of many verbs

An applicative (transitivizing) suffix.

alternative form of -er (agentive suffix)

used to form infinitives of second conjugation verbs

used to create agent nouns from class 1 weak verbs

i-stem/masculine u-stem indefinite nominative plural suffix

feminine i-stem indefinite accusative plural suffix

alternative indefinite nominative/accusative plural suffix for some ō-stems

Used to denote the past infinitive of a verb.

A verb ending for infinitives.

forms the infinitive of the third-conjugation verbs

a verb ending for infinitives

verb suffix for the impersonal present indicative/future

Source: wiktionary.org