Something gross and unapetising, while sometimes cool. it is the best word around. mostly like the F word, it can be used for like anything. its one of those words. a lot of the time it is for a kids face, or mannerism. that is disgusting and repulsive. or just sad.
"dude did you see the fricken kid today? the one with the face?"
"Yeah that kid was god damn gnar, he was basically gnar gnar binks."
"yea he was. damn that kid was so gnar town i wanted to give him the key to the city of gnar town."