adjective

1. grown up; mature in age, size, strength, etc.
2. of or for adult persons an adult novel
3. containing or providing pornography adult movies

Etymology: L adultus, pp. of adolescere: see adolescent

noun

1. a man or woman who is fully grown up; mature person
2. an animal or plant that is fully developed
3. a person who has reached the age of majority, now generally 18 years