Is an abbreviation of the word 'spacmosher' - which is just the word 'space monster' misspelled, however this word has become used to mean retard, spastic, idiot, etc
joe: go buy WoW
dan: no i've played it, it's a kids game and not worth the fee
joe: but...
dan: shut up spac!
Can be defined as 'Going Crazy' or used to describe another living or un-living entities, mental well-being or physicality. Depending on situation where it is used it can be deregatory or complimentary.
The origin of the word 'Spac' according to Brant, comes from the 90's cartoon 'Bucky O'Hare' and is the name of the group the characters belong to. It is painted on the bottom of their spaceship as 'S.P.A.C.e'. Apparantly... I dunno I guess I was pretty mashed at the time, and the cartoon was pretty spac.
'Man, I woke up and my mother just went Spac over nothing.'