to be honest there is 3 definitions of the word 'mong'
1. Adj. Lacking in physical and cerebal ability. General retardation.
Generally: a total spastic
2. Someone in a vegetive state of mind/being usually effective after consuming large quantities of alcohol, weed, lsd, ecstacy etc or combinations of. ie. 'monged'
3. Mong is short for 'mongoloid', which was originally an anachronistic term for a Down's Syndrome sufferer. The modern Mong however is a total fuckwit, who deserves nothing less than complete humiliation for their idiocy. That includes all those dope smokers too, who relate being 'monged' to being chilled and mellow. Its because when you're stoned you act like a fucking retard, you fucking spazzes!
if meant as the shortened form in of 'mongoloid' then VERY OFFENSIVE
he is a prick anyway.