Adjective:

1. (followed by `of') lacking capacity or ability;

   "incapable of carrying a tune"
   "he is incapable of understanding the matter"
   "incapable of doing the work"
   

2. not being susceptible to or admitting of something (usually followed by `of');

   "incapable of solution"
   

3. (followed by `of') not having the temperament or inclination for;

   "simply incapable of lying"
   

4. not meeting requirements;

   "unequal to the demands put upon him"
   

unableadj.不能的；不会的

incompetentadj.无能力的；不称职的；不能胜任的n.没有能力的人

unqualifiedadj.不合格的；无资格的；不适任的；绝对的；无限制的

unfitadj.不合适的；不健康的vt.使不合格

inefficientadj.无效率的；无能的；不称职的

powerlessadj.无力的；无权的；无效能的

ineptadj.不适当的；无能的；笨拙的

inexpertadj.不熟练的；非内行的

helplessadj.无助的；无依靠的

weakadj.弱的；虚弱的；无力的；差的；淡薄的

vulnerableadj.易受伤害的；有弱点的；脆弱的

feebleadj.虚弱的；无力的

frailadj.脆弱的；虚弱的

dependentadj.依靠的；依赖的；从属的

incapacitatedv.使不能；使不适于

unequal to不等于

capableadj.有能力的；能干的；有...的可能性

1. These enzymes are incapable of breaking down or digesting wool,hair or silk fibres which are to them indigestible protein.
   这些酵素压倒或消化羊毛，头发或对他们的丝纤维是无能力的不消化的蛋白质的。