from Wiktionary, Creative Commons Attribution/Share-Alike License
- Of a punch, landing illegally, below the opponent's waist.
- Unfair; dirty; not according to the generally accepted rules.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adv. in an unfair manner
- adj. disregarding the rules (from the notion of an illegal low blow in boxing)
Sorry, no etymologies found.