noun
A reason given to hide the real motive; often used when someone uses something as a cover story.
彼は病気をかこつけにして会議を欠席した。
He used illness as a pretext to skip the meeting.
仕事をかこつけに、彼女はデート
She turned down the date invitation, using work as an excuse.
Derived from the verb 託つける (かこつける), meaning 'to use as a pretext'. The exact historical derivation is uncertain.