笑(わら)い事(ごと)laughing matter

イジメは笑(わら)い事(ごと)では済(す)まされません。

Bullying cannot be dismissed as a laughing matter.

笑(わら)い事(ごと)では済(す)まされない失敗(しっぱい)をして青(あお)ざめる。

I turn pale from making mistakes that can't be dismissed as laughing matters.

同僚(どうりょう)：「僕(ぼく)を含(ふく)めないで会議(かいぎ)をするなんて、笑(わら)い事(ごと)だね。」

Colleague: 'Having a meeting without including me, it's a laughable matter, huh.'

その事故(じこ)で僕(ぼく)は危(あや)うく死(し)にかけたんだ！全(まった)く笑(わら)い事(ごと)なんかじゃない！

I almost died in that accident! It's not a laughing matter at all!

笑(わら)い事(ごと)だと思(おも)っていたことが、犯罪(はんざい)になり得(う)ると知(し)ってヒヤッとした。

I was taken aback when I found out that what I thought was a laughing matter could actually become a crime.