形容詞 incapable:

1. (followed by `of') lacking capacity or ability
2. not being susceptible to or admitting of something (usually followed by `of')
3. lacking the necessary skill or knowledge etc.
   同義詞：unqualified
4. (followed by `of') not having the temperament or inclination for
5. not meeting requirements
   同義詞：incompetent, unequal to

1. Incapable of being expressed; indescribable or unutterable.
   不可言喻的難以表達(dá)的; 難以描敘的
2. That child seems incapable of keeping out of (ie not getting into) mischief.
   那個孩子不調(diào)皮搗蛋簡直就受不了。
3. As a lawyer she's totally incapable.
   她當(dāng)律師完全不合格。
4. The children seem to be totally incapable of working quietly by themselves.
   這些孩子似乎完全不能安靜地自己做功課。

in.ca.pa.ble

adj.（形容詞）

Lacking the necessary ability, capacity, or power:
無能的; 沒用的：缺乏必需的能力、容量或權(quán)力的：
例句：
incapable of carrying a tune; incapable of love.
無法唱得合拍；不能愛

Unable to perform adequately; incompetent:
不勝任的：不能充分履行的；無能的：
例句：
an incapable administrator.
一個不勝任的行政長官

Not admitting or permitting; not susceptible:
不容許的; 無法做的：不容許或不被接受的；不受影響的：
例句：
a unique feat, incapable of duplication.
無法模擬的獨門絕活

Law Lacking legal qualifications or requirements; ineligible.
【法律】 無資格的：法律上無資格或不合要求的；不合法的

【引伸】
inca.pabil.ity 或
inca.pableness
n.（名詞）
inca.pably
adv.（副詞）