Noun: dirty tricks
Usage: informal
- Underhand commercial or political behaviour designed to discredit an opponent
"The campaign was marred by dirty tricks, including spreading false rumours about the candidate"
Usage: informal
Type of: antic, behavior [US], behaviour [Brit, Cdn], caper [informal], conduct, dido [N. Amer, informal], doings, joke, prank, put-on [N. Amer, informal], trick