Wordnet 3.0
ADJECTIVE (1)
1. 
 disregarding the rules (from the notion of an illegal low blow in boxing); 
- Example: "her accusations were below the belt"ADVERB (1)
1. 
 in an unfair manner; 
- Example: "they dealt with him unfairly"- Example: "their accusations hit below the belt"[syn: unfairly, below the belt]
WordNet (r) 3.0 (2006):
below the belt
    adv 1: in an unfair manner; "they dealt with him unfairly";
           "their accusations hit below the belt" [syn: unfairly,
           below the belt] [ant: clean, fair, fairly]
    adj 1: disregarding the rules (from the notion of an illegal low
           blow in boxing); "her accusations were below the belt"