A real, serious fight or duel using real weapons or full force; a contest fought in earnest (not play).
あの二人はもう冗談ではなく、真剣勝負に突入した。
The two of them were no longer joking — they had entered a real, serious contest.
剣道大会では安全対策をした上で、真剣勝負の緊張感がある。
At kendo tournaments, with safety measures in place, there is the tension of a serious bout.
映画では真剣勝負の場面でCGを使わず、本格的に撮影した。
In the film, the real-duel scenes were shot authentically without using CGI.
A contest, game, or match played in earnest — serious competition rather than play.
今日は親子対抗戦なので、真剣勝負でやろう。
Since it's the parent-vs-children match today, let's play it seriously.
面接は真剣勝負だ。失敗は許されないと思って準備した。
The interview is a serious matter. I prepared thinking failure wasn't an option.
友達同士のゲームでも、時々真剣勝負になることがある。
Even in games among friends, sometimes it turns into a serious contest.