IMPERSONAL VERB, in Grammar, a verb to which the nominative of any certain person cannot be prefixed; or, as others define it, a verb destitute of the two first and primary persons, as debet, oportet, &c. the impersonal verbs of the active voice end in t, and those of the passive in ur; they are conjugated through the third person singular of almost all the tenses and moods: they want the imperative, instead of which we use the present of the subjunctive; as peniteat, pugnetur, &c. nor, but a few excepted, are they to be met with in the supines, participles or gerunds.