名詞 incompetent:

1. someone who is not competent to take effective action
   同義詞：incompetent person

形容詞 incompetent:

1. not qualified or suited for a purpose
2. showing lack of skill or aptitude
   同義詞：bungling, clumsy, fumbling
3. not doing a good job
   同義詞：unskilled
4. not meeting requirements
   同義詞：incapable, unequal to

1. He's incompetent and not worth keeping on.
   他庸碌無能，不值得留用。
2. She was put off maths by a bullying and incompetent teacher.
   她對數(shù)學失去了興趣，因為老師仗勢欺人又沒教學能力。
3. He's incompetent; he'll have to go.
   他不稱職，得辭掉他。
4. You incompetent bungler!
   你這個成事不足敗事有余的家伙！
5. An incompetent person.
   無能力者，不勝任的人

in.com.pe.tent

adj.（形容詞）
Not qualified in legal terms:
法律上無資格的：
例句：
a defendant who was incompetent to stand trial.
無資格受審的被告

Inadequate for or unsuited to a particular purpose or application.
不足的，不適合的：對某一計劃或應用不適合或不適當?shù)?/br>Devoid of those qualities requisite for effective conduct or action.
無能的，不適任的：對有效的指導或行動缺乏應有的能力
n.（名詞）
An incompetent person.
無能力者，不勝任的人

【引伸】
incom.petence 或
incom.petency
n.（名詞）
incom.petently
adv.（副詞）