expression, godan verb (-ru)
fall through; come to nothing; be ruined
Colloquial expression for plans, hopes, or efforts ending in failure or being wasted. Often used when something is spoiled or becomes useless.
雨でピクニックがおじゃんになった。
The picnic was ruined because of the rain.
せっかくの計画がおじゃん
Our carefully made plans fell through.