foul play noun
1 criminal activity
VERB + FOUL PLAY suspect | rule out The police have ruled out foul play in the case of his death.
2 play that is against the rules
ADJ. deliberate, serious
VERB + FOUL PLAY be guilty of He was clearly guilty of foul play and deserved to be sent off.
You can also check other dicts: foul play (English, 中文解释 ), wordnet sense, Collins Definition