1. behaving in a way that is silly or immature, like a young child
Usage: often disapproving
2. typical of or suitable for a child
Usage: neutral

Examples

• Stop being so childish and help us solve this problem.
• His childish behavior embarrassed everyone at the meeting.
• She thought his jokes were childish and unfunny.
• The room was decorated with childish drawings and bright colors.
• It’s childish to refuse to talk to someone just because you’re angry.
• Her childish enthusiasm for the carnival was infectious.
• Don’t be childish about losing the game.