Fail A Test, Failure, Rejection
noun
You know that 合格する is "to pass a test," so what's the opposite of that? Fail a test or failure.
ふごうかく
If you know the reading for 合格, all you have to do is add 不 to it! You've learned all these readings, yay!
カンニングしたのがバレて不合格になってしまった。
They found out that I'd cheated and I was rejected.
もしよければ、不合格になった理由を教えてもらえませんか？
If you don't mind, could you tell me the reason I wasn't accepted?
本命の公立大学は不合格だったが、すべり止めで受けた私立大学に合格しました。
I didn't get accepted into my first-choice public university, but I got into a private university that I applied to as a safety.