accido

Accido, accidere, accidi, third conjugation, ad- plus cado: to fall upon, and so to befall, to happen. It has no supine and no perfect participle, which means no passive and no future participle either.

In practice it is nearly always impersonal in the third person, either with a dative of the person it happens to or with accidit ut and the subjunctive, "it happened that". Two traps. First, classical usage skews it towards misfortune: bad things accidunt, good things contingunt, and evenire is neutral. Second, there is a homograph - accido, accidere, accidi, accisum, from ad- plus caedo, "to cut into, cut down" - and the two are separated only by vowel quantity and by context.