whipper-snapper/ˈwɪpə snpə(r); ?@ ˈhwɪ-; `hwɪpɚˌsnæpɚ/ n(dated infml derog 旧, 口, 贬) young and unimportant person who behaves in a cheeky or over-confident way 厚颜无耻的或妄自尊大的年轻人.
牛津英汉双解词典