weakling
词根词缀：
sapling n. 小树苗
sap 树液 + ling 小东西 → 小树苗
seedling n. 幼苗
seed 种子 + ling 小东西 → 幼苗
darkling adv./adj. 在黑暗中（的）
dark 黑暗 + ling 状态 → 在黑暗中（的）
sideling adv./adj. 斜向一边（的）
side 旁边 + ling 状态 → 斜向一边（的）
数据来源：新东方英语词汇速记大全
相关例句：
They beat up on a weakling. that's all they did.
他们以强凌弱，这是事实。
I'm a useless weakling, and I can't stand excitement.
我没有胆量去承受那激动，我还是希望我能不见着他。
The moment I show my face at the imperial city, that weakling Wuhuan will submit without question!
只要我一个人出现在王城，北公爵无欢就不战自溃。
He was ineffective, not exactly a weakling, but ineffective.
他办事没效率，倒也不完全是个无能之辈，就是不干练。
An insipid weakling who is foolishly sentimental.
愚蠢而感情脆弱的一个乏味的体弱的人。
He gradually realized that he was what Westerners called a "moral weakling," and was worried that Miss T'ang would detect this major flaw in his character.
他渐渐明白自己是个西洋人所谓“道义上的懦夫”，只怕唐小姐会看破了自己品格上的大弱点。