Dictionary / Vocabulary / ぬか喜び
ぬかよろこび
premature joy; short-lived elation
Also written 糠喜び
君、本当に企画通ったこと確認しただろうね。糠喜びだけはごめんだよ。
Are you saying that our plan was accepted? I hope you're not showing me any premature happiness here.