def-bombing
Attacking an Urban Dictionary definition with a sustained barrage of thumbs-down votes.
The definition had been selected as Word of the Day. It had earned thousands of thumbs-up votes and many fewer thumbs-down. But somebody out there was peeved. Every day they contrived to give it as many thumbs-downs as they could, usually four or five, in an act of def-bombing that only underscored the power of the definition itself.