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2.
"Never date a co-worker." From the all-important (and sometimes hypocritical) rules of Leroy Jethro Gibbs of NCIS.
Ziva: "Tony, we cannot break Rule 12."
Tony: "Why not? Gibbs and Jenny totally did."
by dinozzosgirl February 07, 2010
 
1.
Romance between coworkers never works out.

(Originated from S.A. Gibbs' unwritten Rules, per NCIS)
TONY: I love you, Kate, but we can't break Rule 12!
KATE: Screw Gibbs and his rules! We belong together.
by MissNoodles June 23, 2006
 
3.
Downloading unnecessary porn when you are horny, then deleting after finished.
After I finished looking at porn, I rule 12'ed the torrents I was downloading while horny and fapping, by going back after I was done and deleted the downloads in progress.
by Psilocybe Tim March 14, 2008
 
4.
An amazing website similar to sythe(dot)org, but only in the sense that Rule-12.com is dedicated to Runescape cheating. This website consists of different forum sections pertaining to general discussions, graphics, computer programming etc. Rule-12 members are noticeably more respectful and polite than most other forum users. Overall, Rule-12(dot)com is the epitome of Runescape Cheating/Black Market websites.
Loser: Hey man, come to sythe!!!11!!

Better Person: And get hacked, scammed, and spammed? No thanks, i'll go to Rule-12
by Rule-12 December 28, 2008