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Member of Opposite Sex.
I have engaged in foreplay with an M.O.S.
by Dash_Morlock July 20, 2010
man of steel (or 'men')

the 'macho man' who has huge pain tolerance, physically OR emotionally!; ESPECIALLY WHEN DRUNK!!
jack was a true M.O.S.!! he took on some killer bikers and got seriously thrashed, but bounced back like a turd that wouldn't flush!

he didn't know what he was in for challenging those M.O.S.

the special op M.O.S. kept on shooting after losing part of a leg, until he keeled over from blood loss!
by michael foolsley February 12, 2010
M.O.S.=Member of Society:

someone who works, doesn't live with his parents and has a girlfriend. As well as this he does things regualr people do like go to the gym, wear a suit to work and buys beers in rounds at the pub.
that boy wears a suit to work, he's an M.O.S.

I saw him jogging with his girlfriend, what an M.O.S.

mate he's busy being an M.O.S. he ain't gonna come out.
by Safety190 August 28, 2010
Stands for Ministry of Sound, a highly successful nightclub in London where they play electronica and stuff.
person a: did you get that mos annual cd?
person b: why dont you go to my amazon wishlist and buy it for me
person a: ok!
by Steven Bao August 02, 2006
Mom over shoulder, often said in AIM to keep the reciever of the message from saying something particuarly "nasty" or "questionable"
UT4k2:What the hell does that mean?
Darkbob101:Too late...
by Connor September 30, 2004
make out slut.
Naw, she's an MOS.
by makeoutslut June 01, 2010
Man on the side; meaning a man you have secretly in addition to your current relationship. Sometimes developes into a boyfriend/girlfriend relationship.
I'm going to LA to meet my MOS for a great weekend away from the hubby.
by Cali 521 July 22, 2008