foul play

uncountable

Unfair, unethical, or criminal behavior, especially of a malicious or violent nature. / Any violation of rules.

Japanese Meaning

不正行為（不当で不倫理、または犯罪的な行動） / 悪意や暴力を伴う場合がある不正または犯罪的行為 / 規則違反

After examining the scene, the coroner found no signs of foul play.

検視官は現場を調べたが、犯罪性や悪意のある行為の証拠は見つからなかった。

Sense（1）

Unfair, unethical, or criminal behavior, especially of a malicious or violent nature.

"I think there's been foul play," said Poole, hoarsely.

Sense（2）

Any violation of rules.