look up any word, like wyd:
 
1.
Hells no is worse then "Hell no." Hence the "s" after Hell.. which implies that that it is multiple Hells making it worse then only a single Hell.
Bro - Go to the Kenny Chesney concert with me
Me - Hells no. Kenny Chesney is a fag.
by SirLeche May 02, 2005
 
2.
Another way of saying no with "Ooomph". Used when laying it on thick and trying to let someone know you don't want whatever the fuck they are selling.
Guy: wanna play tekken 5 and then make out?
Gurl: hellsno
by B March 31, 2005