I. ad ‧ ult 1 S2 W2 AC /ˈædʌlt, əˈdʌlt/ BrE AmE noun [countable]
1 . a fully-grown person, or one who is considered to be legally responsible for their actions ⇨ child :
Some children find it difficult to talk to adults.
2 . a fully-grown animal:
The adults have white bodies and grey backs.
II. adult 2 W3 AC BrE AmE adjective
[ Date: 1500-1600 ; Language: Latin ; Origin: past participle of adolescere 'to grow up' ]
1 . [only before noun] fully grown or developed:
an adult lion
the adult population
He lived most of his adult life in Scotland.
2 . typical of an adult’s behaviour or of the things adults do:
dealing with problems in an adult way
That wasn’t very adult of you.
3 . [only before noun] adult films, magazines etc are about sex or related to sex:
The film is rated R for language and adult themes.