Wiktionary
n. (dirty trick English)
WordNet
n. underhand commercial or political behavior designed to discredit an opponent
Wikipedia
Dirty tricks are unethical, duplicitous, slanderous or illegal tactics employed to destroy or diminish the effectiveness of political or business opponents. The term "dirty trick" can also be used to refer to an underhanded technique to get ahead of an opponent (such as sabotage or disregarding rules of engagement).
Dirty Tricks is a 1981 American comedy film directed by Alvin Rakoff and written by William W. Norton, Eleanor E. Norton, Thomas Gifford and Camille Gifford. The film stars Elliott Gould, Kate Jackson, Rich Little, Arthur Hill, John Juliani and Alberta Watson. The film was released on March 6, 1981, by AVCO Embassy Pictures.
Usage examples of "dirty tricks".
In age, height and weight the two master mariners were pretty evenly matched and if Captain Griffiths was a bit fitter Fleck knew more dirty tricks.
Elder probably had had courses in karate, savate, and general dirty tricks.
Sam got the impression they knew the grounds very well, and had a few hundred dirty tricks ready.
I'd almost forgotten that I'd ever been worried about Hilary and her dirty tricks.