weak/weakly/weaken/weakness

weak /wi:k/ adj. 1. 弱的 (指体力) (［反］strong): She felt very weak after her illness. 病后她觉得很虚弱。2.差的：He is weak in mathematics, but good at English. 他数学差，但英语好。

［辨析］weak用来形容身体乏力，性格不坚强或意志力薄弱，feeble⁶则表示由于乏力致使动作不连贯、不正常，表现为缺乏机智或灵活，形容事物时，表示微弱或不足，如：feeble-minded; a feeble light

weakly adv.虚弱地

 weaken /ˈwi:kən/ vt. & vi.(使)变弱，削弱：We never weaken our efforts in face of difficulties. 我们在困难面前绝不松劲。The illness weakened her heart. 疾病使她的心脏衰弱了。She’s weakening - ask her some more questions and see if she confesses.她软了，再多问她一些问题看她是否承认。

 weakness /ˈwi:knis/ n. 1.［c］虚弱，衰弱，软弱: the weakness of old age 老年的虚弱；the weakness of his character 他性格的脆弱 2.［c］弱点，缺点：We all have our little weakness. 我们都有小缺点。 Hardly anyone is without weaknesses of character. 几乎无人性格上没有弱点。