poor sport

Noun

Someone who exhibits ungracious behaviour during a game, whether winning or losing. / Someone who cannot take a joke.

Japanese Meaning

試合中に礼儀正しさを欠く振る舞いを示す人、勝っても負けても不遜な態度をとる者 / 冗談すら受け入れられない、人としての立ち振る舞いが未成熟な者

Even after winning, he was a poor sport and refused to shake hands.

勝っても、彼はスポーツマンシップに欠ける人で、握手を拒んだ。

Sense（1）

Someone who exhibits ungracious behaviour during a game, whether winning or losing.

Sense（2）

Someone who cannot take a joke.

poor sports

（ plural ）