unfit; incompetent; unsuitable
Used to describe a person who is not suitable for a position, role, or task due to lack of ability or character. Often used in formal contexts such as job evaluations or official statements.
He was judged unfit for the job.
You should not place an incompetent person in a managerial position.
無能 is a stronger, more direct term for incompetence or inability, often used as a blunt criticism, whereas 不適任 is more formal and situational.
Compound of 不 (not) + 適任 (suitable for a post). 適任 itself is from 適 (suitable) + 任 (duty, responsibility).