He wasn't enjoying the occasion so he thought he'd spoil it for everyone else - it was very childish of him.
- How very childish of her to refuse to speak to me!
- I've had enough of your childish pranks.
- "Stop this childish nonsense at once!" he shouted furiously.
- Don't be so childish - just give me the keys and stop messing about.
- She said we should be ashamed of our childish behaviour - fighting over who got the last strawberry.
adverb uk /ˈtʃaɪl.dɪʃ.li/ us /ˈtʃaɪl.dɪʃ.li/ disapproving
noun [ U ] uk /ˈtʃaɪl.dɪʃ.nəs/ us /ˈtʃaɪl.dɪʃ.nəs/ disapproving