whippersnapper
noun [ C ] old-fashioned or humorous uk/ˈwɪp.əˌsnæp.ər/ us/ˈwɪp.ɚˌsnæp.ɚ/
妄自尊大的年轻人，自命不凡的年轻人
a young person who is too confident and shows no respect towards other, especially older, people
I'm not going to have some young whippersnapper tell me what to do! 我可不需要什么不知天高地厚的年轻人来告诉我应该做什么！