To smack someone on the back of the head with an open hand. Derived from the trademark slap delivered by the character Leroy Jethro Gibbs to his underlings on the T.V. show N.C.I.S. To deserve a 'gibbs' or a 'gibbs-smack' the person getting it should have done something stupid, vain or dangerous.
When I found out he was cheating on his gf that was one thing; when I found out the asshat was hitting on jailbait in her favorite bar, I gave him a gibbs he'll never forget.
by shoopyou March 30, 2009
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I have got a couple of gibbs in me purse. OR I ain't got any gibbs to go out tonight.
by Ems August 5, 2003
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n. A re-raise in a game of poker that is less than the bet being raised.

alt. to "Pull a Gibbs"
We were playing texas hold-em, and I bet a quarter. Then some jackleg pulled a gibbs and raised it a nickel. That's so ghey.
by Douchetard May 7, 2003
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1. To steal something.
2. To rip someone off.
1. "Hey can I have a drink of your soda?"
"No way, you gibbsed my last one"

2. "I payed thirty bucks for this bag but it didn't weigh out and it was full of seeds."
"Man, it sounds like you got gibbsed."
by Ziggilus October 25, 2007
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often referring to a man who enjoys wearing women's clothing

or

slang meaning homosexual male who joins a sports team, particularily a wrestling team, to be closer to fellows males without drawing suspision
Wow, that kid sure is a gibbs. He had the nerve to ask to borrow my bra. Like he could even fill by bra with his measley A cups..
by houdini89 December 9, 2005
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the part of the neck between the jaw and the throat
"you'd better shut up or i'll hit you in the gibbs!"
by buck February 19, 2004
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used in chat/AIM slang as a way to denote that the other person has just received a minor slap to the back of the head, like what Leroy Jethro Gibbs gives his team.

The slap is a punishment, usually done when the person has done/said something stupid.

Can be used as an expression of aggravation
H0tChick101: I met this hot guy...
TalkaTalk20: His name?
H0tChick101: James. He's tall, auburn haired, and hazel eyed.
TalkaTalk20: <Gibbs>. That's my boyfriend.

DiNozzo: I've got this great new toy
McGee: Great, now we won't hear the end of it
DiNozzo: <Gibbs> Probie, come on
by Sans0uAvecV0us March 23, 2009
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