gibbs slap 

A slap upside the back of the head usually done to someone who did or said something stupid. It was invented by Leroy Jethro Gibbs.

DiNozzo: "An assisted suicide of a suicide bomber whose suicide was before his suicide bombing. It's like how much wood can a woodchuck chuck if a woodchuck could chuck..."
Gibbs gibbs slaps him.

gibbs slap by mcabbyshipper January 17, 2013

Gibbs-slap 

A sharp, upward slap to the back of the head given to someone acting blaringly stupid. Originated from Special Agent Gibbs from NCIS who employs this manuver often.

"Dude, your mom is so hot."
*Gibbs-slap*
"What? Well she is..."

Gibbs-slap by plataypusIhateyou October 7, 2005

Gibbs Slap 

Made famous by Special Agent Leroy Jethro Gibbs (Mark Harmon) on the t.v. show NCIS, this is an open-handed slap to the back of the head. This is usually done in response to an act of stupidity. Done in a half-serious way to show power.

Once at work, I was playing Tetris on my computer. When the boss saw, he Gibbs slapped the hell outta me!

Gibbs Slap by Mr._ December 2, 2009

Gibbs slap 

When someone's stupidity is so painful to watch that the pain has to be shared via a open-handed slap to the head.

John: *overwhelmingly idiotic jibber-jabber*
Suzy: I'm about to Gibbs slap you if you don't shut up.

Gibbs slap by this one's for you, jess July 2, 2017

Gibbs Slap 

A slap upside the back of the head a la Leroy Jethroe Gibbs from NCIS usually done to someone who did or said something stupid.

Don Gibbs slapped after I asked him to shower with him.

Gibbs Slap by legaykidd May 22, 2009

gibbs-smacked 

when one smacks someone else on the back of the head like Agent Gibbs does on NCIS. Usually done to Agent DiNozzo

DiNozzo said something stupid then Gibbs gibbs-smacked him on the back of the head

gibbs-smacked by they call me fluffy March 19, 2010

Gibb's Second Law 

Coined by Gibbs himself, it is short for 'Gibb's second law of relational-dynamics'

It states that:

Relationships between members in a squad will not last for long and when they do end they will tend towards the detriment of the squad as a whole and will probably involve a lot of angry paras sent over iMessage and/or Whatsapp.

Person 1: "Did you hear that Sarah and Matt broke up?"
Person 2: "Yeah, I had 374 unread messages on Whatsapp"
Person 1: "What can you do, it's just Gibb's Second Law!"

Gibb's Second Law by Slow-winky February 14, 2017