weak的名词是weakness；
weak
adj.虚弱的;无力的;不牢固的;易损坏的;易破的;易受影响的;懦弱的;软弱无力的；
比较级 weaker；
最高级 weakest
He became very weak towards the end of his life.
他临终时很虚弱。
He was a weak little mouse of a man.
他是个懦弱无能的人。
I was always weak in the science subjects.
我总是学不好理科。
水利万物而不争,
而万物莫能与之争。
