childish Get Printable Handwriting (child-ish) 2 syllables Rhymes Learn It! Spelling Test Definition adjective. typical of or fit for a child; marked by weak foolish or immature behavior. Example Sentence My brother is behaving very childish. Synonyms babyish; immature; juvenile Antonyms adult; grown-up; mature Rhymes Two Syllable Rhymes (1) childish Share with your friends: