Vieillir belong to the 2
nd group. Vieillir is a common french verb.
Vieillir is conjugated the same way that verbs that end in :
-ir
Vieillir is conjugated with the two auxiliaries
être and
avoir.
Vieillir verb is
direct transitive, intransitive.
French verb vieillir can be conjugated in the reflexive form:
Se vieillir
Vieillir verb is a direct transitive verb, so passive voice can be used.
Attention: passive voice can only be used when vieillir verb is conjugated with auxiliary avoir.