look up any word, like demiromantic:
 
1.
One Special Mother Fucker

Mainly used to describe young coworkers that think they are the shit.

Also used for anyone whos shit don't stink.
Andy sure thinks he is OSMF, what a flaming douchebag!
by Carpmaster November 21, 2008
 
2.
Oh Shit MotherFucker
'OSMF' did you see that ?!?!?!
by RussY757 August 21, 2010