笑い事じゃないよ。

笑い事じゃないよ。

It's no laughing matter.

笑(わら)い事(ごと)じゃないよ。

Waraigoto janai yo.

笑い事 (わらいごと)

laughing matter

じゃあ (じゃあ、じゃ)

then; well; so; well then; combination of 'de' and 'wa' particles; plain copula

よ (よ)

indicates certainty, emphasis, contempt, request, etc.; used when calling out to someone; used to catch one's breath or get someone's attention; yo!

Readings: ショウ、わら.う、え.む

Meaning: laugh

Readings: ジ、ズ、こと、つか.う、つか.える

Meanings: matter, thing, fact, business, reason, possibly