OMFJC: Oh My Fucking Jesus Christ...a more forceful and vulgar way of saying, the more common, Oh My God (OMG)or Oh My Jesus Christ (OMJC).
OMFJC is considered the "Lords Name in Vain" when spoken without abbrieviation so beware when using.
Person 1: OMFJC!!! I totally just failed that test!!!
Person 2: Dude...lords name in vain. Keep it down
Person 1: Nah...i abbrieviated. No biggy