Abbriviated xMUSTACHExCOREx or simply mxc
1. Used when something is too hardcore to be called hardcore and must move up to an even better word.
2. Also to be used when you see a man (or ugly woman) with an intense mustache that likes, preforms in or is at at super duper hardcore show.
1. cool doood: hey douchebag,did you see that sick nasty nollie bigflip? it was totally mustachecore!
fag: fo sho!
2. another cool d00d: hey i saw this guy at mcdonalds wearing a liferuiner shirt and he had a crazycool handlebar mustache like muthafuckin hulk hogan!!. he'sprobably part of the next XXXmustacheXXcoreXXX band.