from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Slang Unjust or dishonest conduct.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Foul play, misconduct.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. conduct that is unfair or unethical or unsportsmanlike
From pool2.(American Heritage® Dictionary of the English Language, Fourth Edition)
Probably an allusion to failing to follow the rules when playing billiards. (Wiktionary)