My old teacher saved his whole platoon in Nam by jumping on a land mine -- but damn that crazy was fugnasty.
syn. = fugly, just ruder, to be used at the end of a sentence only, with a hard quick emphasis on the FUG part. This is astepping stone to the use of the F-word in more everyday contexts.
Similar to fucking nasty, but with the ommitence of the "uck" and the "ug" in its place, bringing with it an element of offensive ugliness similar to "fugly". To break it down would give you the three words: fucking ugly nasty
Those chili-cheese burgers from Carls Junior look fug nasty.