(also spelled "insignifiCUNT") - a person that is too worthless for any other adjective. Please note: gender unrelated! Rush Limbaugh is at least as worthy a poster-child as Ann Coulter or the moronic 26 year old meth-freak that burned down the 5th oldest tree on the planet.
(sung to the tune of a Warner Brothers + Sisters theme)
You're an insignifiCUNT!
I should kick you in your FRONT!
You're a big, fat, stupid stoop -
and, you prematurely droop -
You're an in•sig•ni•fi•CUNT!