1) Befitting a young child 2) Childish 3) Childlike 4) Immature 5) Young 1) Childlike 2) Young 
• (a.) Having the character of a child; belonging, or appropriate, to a child. • (adv.) Like a child.
Child'ly adjective Having the character of a child; belonging, or appropriate, to a child. Gower. Child'ly adverb Like a child. Mrs. Browning. 
childlike; childish.