Definition of adults:
(n) :
A person who has reached the legal age of majority.
(adj) :
Fully grown.
(n) :
An animal that is full-grown.
(adj) :
Intended for or restricted to adults rather than children due to size, maturity, knowledge level, judgement, etc.
(adj) :
Containing situations or discussions intended primarily for adults, such as serious crime, illicit drug use, extramarital affairs, etc.
(adj) :
(of a beverage) Containing alcohol, intended for consumption only by adults.