Mon (pronounce "mun") is an abbreviation for the term "money". It is used for anything or anyone that is totally legit and fuckin' rad. It has the same general meaning as the term "money", but is used by mon individuals who are too busy living the dream and fucking shit up to be bothered to pronounce the whole word. Mon is more than a word, it's a way of life. It is thought to have come into existence at the University of Idaho around '09 or '10.
"Dude, last night was so fucking mon." "Yeah man, I finally hooked up with Jenny. Mon!" "That shit is so mon, dude."