consenting adult
noun /kənˌsentɪŋ ˈædʌlt/, /kənˌsentɪŋ əˈdʌlt/
/kənˌsentɪŋ əˈdʌlt/, /kənˌsentɪŋ ˈædʌlt/
- a person who is considered old enough, by law, to decide whether they should agree to have sex; a person who has agreed to have sex
- What consenting adults do in private is their own business.