foul play

foul play (uncountable)

Unfair, unethical, or criminal behavior, especially of a malicious or violent nature.
- 1886 January 5, Robert Louis Stevenson, Strange Case of Dr Jekyll and Mr Hyde, London: Longmans, Green, and Co., →OCLC:
  "I think there's been foul play," said Poole, hoarsely.
- 2023 October 30, Sian Cain, “Friends stars release statement after death of Matthew Perry: ‘We were more than just castmates’”, in The Guardian‎, →ISSN:
  An autopsy, pending a toxicology report, would determine the cause of death, the Los Angeles county medical examiner said. Foul play was not suspected, said Cap Scot Williams, who leads the city’s police robbery homicide division that is investigating Perry’s death.
Any violation of rules.

unfair, unethical, or criminal behavior

Chinese:
Mandarin: 犯規行為 / 犯规行为 (fànguī xíngwéi)
Finnish: vilunkipeli (fi)
French: mauvais coup m, coup tordu (fr) m, acte de malfaisance f
German: Foulspiel (de) n, Foul Play n
Hungarian: bűncselekmény (hu), erőszak (hu), idegenkezűség (hu)
Japanese: ファウル (ja) (fauru), 不法行為 (ja) (ふほうこうい, fuhō kōi)
Polish: faul (pl) m
Portuguese: jogo sujo m, infração (pt) f, delito (pt) m, falta (pt) f
Russian: нече́стная игра́ f (nečéstnaja igrá), гря́зная игра́ f (grjáznaja igrá), гру́бая игра́ f (grúbaja igrá), игра́ не по пра́вилам f (igrá ne po právilam)
Spanish: juego sucio m

violation of rules

Chinese:
Mandarin: 違反規則 / 违反规则 (wéifǎn guīzé)
Finnish: vilppi (fi)
French: faute (fr) f, infraction (fr) f
German: Verletzung der Regeln f
Hungarian: szabálytalanság (hu), tisztességtelenség (hu), becstelenség (hu), csalás (hu)
Indonesian: pelanggaran (id)
Japanese: 不正行為 (ふせいこうい, fusei kōi)
Portuguese: transgressão (pt) f, infração (pt) f, delito (pt) m, falta (pt) f, ofensa (pt) f
Russian: наруше́ние пра́вил n (narušénije právil)
Spanish: juego sucio m

English