Short for "only child syndrome." Can be associated with selfishness, rudeness, laziness, and/or arrogance, but is not limited to these things. OCS may also be accompanied by strange/unexplainable side effects, i.e. excessive computer-nerdiness, knowledge of the names/charicteristics of people who do not know you, the need to bite inatimate objects or others, the need to snuggle with those you have just fought with, the urge to tickle/poke others for no apparent reason, and many other habits that vary by individual.
Person One: How does Angie know so much about hooking up her new computer?
Person Two: She's got OCS.

Person One: What are you doing?
Only Child: -bites Nintendo DS-
Person Two: Oh, don't mind her. She's got a bad case of OCS.
by jenomi June 9, 2009
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OCS is commonly recognised in the UK as the "One Complete Solution" company and their vans are often seen of the roads of our major citys. According to some muppet in the USA, OCS also stands for "Original Chicken Sandwich" and uses the example of "I really fancy an OCS"

As any self respecting porno-mag reader will know, OCS stands for "Open Cunt Shot" - a standard pose of your hardcore porno models where they lie back and pull their pussy apart for the camera.

I suggest our American friend doesn't use his example whist on holiday in the UK as he could end up with a well thumbed copy of Whitehouse being slipped into his sweaty palms!!
Jeesus, check that OCS out

Whilst in the bedroom with your good lady; "Come on luv, stop mucking about and give me an OCS"

(snigger) "There's the OCS Van!!)
by Threedeckwizard July 27, 2006
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An acronym for "Original Chicken Sandwich", which is the deal of the day for Tuesday at Burger king.
maen: Are we goin for an OCS?
maen 2: I already went with the boys during spare
maen: You fuck! Wait till lunch to go for an OCS sesh!
by Kayounit May 9, 2006
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Occasional Cock Sucker
I knew Kevin was an OCS by the way he always wanted to be alone with Josh.
by shellhunter June 12, 2011
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"only child syndrome"

the act of hogging everything to yourself as if you were an only child.
"i was trying to play x-box, but billy has OCS and wont let me play."
by jenna taliah March 13, 2009
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Only Child Syndrome - A person that has no brothers or sister. Has an extreme sense of possession. Always needs to feel like he or she is the best and most accomplished. Needs to be reassured of his or her superior standing constantly. They also use the two "M" words a lot "My", "Mine". This person will lash out and become defensive if they are called out on any of this "OCS Behavior".
John: "Can I use your pencil for a second."

OCS Person: "No it's mine."
by Doctor Kenneth Noisewater September 19, 2008
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OC means out of control. Usually DMV talk (D.C., Maryland, Virginia)
Yo g that shit is OC wack!
by the coolest motherf June 22, 2019
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