1.weakness的基本意思是“弱,软弱,虚弱,薄弱”,指某人的身体状况不佳或指某事不够完善的一面,也可指某人或某事的缺陷,即“弱点,缺点”。weakness引申可指“偏好,嗜好”“宠爱的人或东西”等。weakness作“虚弱,软弱”解时是不可数名词,作具体的“弱点,缺点”或“嗜好,偏好”解时是可数名词。
2.weakness作“偏好,嗜好”解时,常用于have a weakness for短语中。

She is still suffering from the weakness attendant on the illness.她还在经受伴随着疾病而来的虚弱。
The patient's weakness is due to poor nutrition.这位病人的虚弱是由营养不良引起的。
The president was accused of weakness in dealing with the crisis.人们指责总统在处理危机时软弱无力。
He agreed in a moment of weakness to go along.他因一时软弱而同意照办。
He succeeded in his efforts to overcome his fatal weakness.他努力克服了自己致命的弱点。
Drinking is his weakness.他的缺点是爱喝酒。
We all have our weaknesses.我们都有不足之处。
She's my weakness now.她现在成了我的心上人。
▲～+for n./pron.
I have a weakness for peanut jam.我偏爱花生酱。
He has a weakness for detective stories.他特别爱读侦探小说。
He has a weakness for money.他爱钱如命。
▲～+of n./pron.
New evidence revealed the weakness of the prosecution's case.这一新的证据表明原告理由不充足。
How well do you know the weaknesses of women?你对女人的弱点了解多少?
Can't you see the weakness of his argument?你看不出他的论点的缺陷吗?
Smoking is a weakness of his.他的嗜好是抽烟。

1.由于身体虚弱,他不能再帮助我了。
［误］  Because of his weaknesses, he could not help me any more.
［正］  Because of his weakness, he could not help me any more.
［析］  weakness表示“虚弱”时是不可数名词,不能用于复数形式。
2.她只知道别人的缺点。
［误］  She is only aware of the weakness of others.
［正］  She is only aware of the weaknesses of others.
［析］  weakness表示“缺点”时是可数名词,有复数形式。
3.他特别爱读故事。
［误］  He has a special weakness in stories.
［正］  He has a special weakness for stories.
［析］  作“特别喜欢…”解时,应该说have a special weakness for,其中介词for不可改为in。

［同义词］   failing, soft