expression, godan verb (-u)
feign illness; pretend to be sick
Used when someone fakes being ill, often to avoid work, school, or an obligation.
彼は学校を休むために仮病を使った。
He feigned illness to skip school.
仮病を使っても、すぐにばれてしまうよ。
Even if you pretend to be sick, you'll get caught right away.