the act of doing something so gnarly it isn't even gnar anymore its the hybrid lesbian sister of both hardcore and gnarly. also "GNARCORE" means nothing if there is a hyphen between "GNAR" and "CORE" and if its not spelled with all capitols or yelled!
dude 1: anthony's toe-nail surgery was so gnar.
dude 2: no way man, that ish was GNARCORE
dude 1: ...thats as good as the english language will ever get!