1. (a.) Having arrived at maturity, or to full size and strength; matured; as, an adult person or plant; an adult ape; an adult age.

2. (n.) A person, animal, or plant grown to full size and strength; one who has reached maturity.

aged big full-blown full-fledged full-grown grown grown up grown-up marriable marriageable mature matured maturescent nubile of age of marriageable age old ripe ripened