Incompetence is the noun: the lack of the skill or ability to do a job properly. If someone keeps making serious mistakes at work, people may talk about their incompetence — they cannot do what the job needs.

Incompetence is the nounincompetence是名詞 the lack of the skill or ability指的是缺乏技能或能力 to do a job properly把工作做好 If someone keeps making serious mistakes at work如果有人在工作上一直犯嚴重的錯 people may talk about their incompetence大家可能就會說他incompetence（無能） they cannot do what the job needs因為他做不到這份工作需要的能力

This is a hard, formal word. In an office it is not a gentle note; it is a strong claim that someone is unfit for the work. News and reports use it; friends more often say someone is bad at the job, or cannot do it.

This is a hard, formal word這是一個很重、很正式的字 In an office在辦公室裡 it is not a gentle note這不是溫和的說法 it is a strong claim而是很重的一句話 that someone is unfit for the work說某人不適任這份工作 News and reports use it新聞和報告會用這個字 friends more often say但朋友之間比較常說 someone is bad at the job, or cannot do it某人不擅長這份工作，或做不來

Though actually, law and medicine also use incompetence for a person who cannot legally make decisions for themselves, for example after a serious illness. That is still “not able,” but about rights and care, not about being bad at a task.

Though actually不過其實 law and medicine also use incompetence法律和醫學也會用incompetence這個字 for a person who cannot legally make decisions for themselves指一個在法律上無法為自己做決定的人 for example after a serious illness例如生了一場重病之後 That is still 'not able,'這仍然是「無法」的意思 but about rights and care但講的是權利和照顧的問題 not about being bad at a task而不是講某人不擅長做某件事

For school English, start with the job sense.

For school English對學校英文來說 start with the job sense先從工作能力這個意思學起就好