below the belt

Từ điển WordNet v3.1 - WordNet Dictionary

I - adjective

disregarding the rules (from the notion of an illegal low blow in boxing)
- her accusations were below the belt
• Similar to:
unfair, unjust
• Topics:
boxing, pugilism, fisticuffs

II - adverb

in an unfair manner
- they dealt with him unfairly
- their accusations hit below the belt
• Syn:
unfairly
• Ant:
fairly (for: unfairly)
• Derived from adjective:
unfair (for: unfairly)