childish 4 antonyms and opposites of childish. Adj — Behaving in an immature way, typically expected only of a child. Synonyms for childish immature silly unbecoming juvenile puerile kiddish child babish babyish bairnish dootsie hissy lactifluous infantine milky Antonyms for childish adultish mature adult adultlike ← Back to the full definition of childish
