Definition of adults-only in English:

adults-only

adjective

  • Intended for or restricted to adults; specifically (of books, films, etc.) unsuitable for or prohibited to children because of violent or sexually explicit content.

Origin

Early 20th century; earliest use found in The Chicago Defender. From adults, plural of adult + only.

Pronunciation:

adults-only

/ˌadʌltsˈəʊnli/