infin

a verb form found in many languages that functions as a noun or is used with auxiliary verbs, and that names the action or state without specifying the subject, as French venir “to come,” Latin esse “to be,” fuisse “to have been.”

(in English) the simple or basic form of the verb, as come, take, eat, be, used after auxiliary verbs, as in I didn't come, He must be, or this simple form preceded by a function word, as to in I want to eat.

consisting of or containing an infinitive: an infinitive construction. Abbreviation: infin.