1. infirmity /ɪn'fɜ:mətɪ/ n. 虚弱

   --weakness; feebleness; frailty

On leaving the hospital, the patient felt almost too weak to walk, but he soon overcame this infirmity.

离开医院时，病人感到虚弱得几乎走不动，但他很快就克服了虚弱。

2. debilitate /dɪ'bɪlɪteɪt/ vt. 使虚弱

    --impair the strength of; enfeeble; weaken

The patient had been so debilitated by the fever that he lacked the strength to sit up.

这病人因发烧而一直很虚弱，以至于连坐起来的力气都没有。

3. enervate /'enəveɪt/ vt. 使无力

    --lessen the vigor or strength of; weaken; enfeeble

Enervated by the heat, we rested under a shady tree until our strength was restored.

热得没力时我们坐在一棵阴凉的树下休息，直到力气恢复了为止。

4. incapacitate /ˌɪnkə'pæsɪteɪt/ vt. 使不能

    --render incapable or unfit

Ruth will be absent today. She is incapacitated by a sore throat.

露丝今天将缺席，喉咙痛使她不能出席。

5. decadent /ˈdekədənt/ adj. 衰落的

    --marked by decay or decline; falling off; declining; deteriorating

When industry moves away, a flourishing town may quickly become decadent.

工业迁走时，一个繁荣的城镇很快就会衰落。

6. decrepit /dɪˈkrepɪt/ adj. 老朽的

    --broken down or weakened by old age or use; worn out

Bill rode past the street on a horse that looked decrepit and about to collapse.

比尔骑着一匹看上去快倒了的老马从街上经过。

7. dilapidated /dɪˈlæpɪdeɪtɪd/ adj. 荒废的

    --falling to pieces; decayed; partly ruined or decayed through neglect

Up the road was an abandoned farmhouse, partially in ruins and near it was a barn, even more dilapidated.

沿那条路走下去，有一间部分毁坏的废弃农舍，农舍附近有一个谷仓，荒废得更厉害。

8. flimsy /'flɪmzɪ/ adj. 薄弱的

    --lacking strength or solidity; frail; unsubstantial

Judy understands algebra well but I have only a flimsy grasp of the subject.

朱迪精通代数，但我对这科目却掌握得不好。

9. frail /freil/ adj. 虚弱的

    --not very strong; weak; fragile

To be an astronaut, you muat be in robust health. It is not an occupation for a frail person.

当宇航员必须身体强壮，身体虚弱的人不适合从事这个工作。