Definition of "adult"

A fully grown human or animal.  quotations  examples

A person who has reached the legal age of majority.  examples

Fully grown.  quotations  examples

Intended for or restricted to adults rather than children due to size, maturity, knowledge level, judgement, etc.  quotations

1. Containing situations or discussions intended primarily for adults, such as serious crime, illicit drug use, extramarital affairs, etc.  examples

2. (of a beverage) Containing alcohol, intended for consumption only by adults.  examples

3. (of a cookie, gummy, etc.) Containing marijuana, intended for consumption only by adults.  examples

4. Containing material of an explicit sexual nature; of, or pertaining to, pornography.  examples

5. Containing excessive vulgar or profane speech, text or images, intended only for adults.  examples

(intransitive, informal) To behave like an adult.  examples

(nonstandard, rare) To (cause to) be or become an adult.  quotations