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14.
A penis that has a premature ejaculation problem;
Having no safety on his gun
Lucas has a loose cannon. He was hooking up with this one chick and he blew his load in his pants.
by Dome Froggie December 18, 2007
 
1.
In the days of sail, naval vessels mounted cannon carefully and purposefully rigged into positions which optimised the effect of their fire. Occasionally, the rigging of these very heavy guns might come loose, and with the vessel pitching about on high seas or during manuever in battle, the results for the ship and crew could prove catastrophic. The term has come to describe a person lacking prudence or insight, whose actions and/or speech jeopardises the safety of people in their proximity or under their authority.
Like a drunken bully, the politician shrugged off his advisors and taunted the insurgent forces operating in the country his armies were attempting to pacify. He had become a LOOSE CANNON.
by crowbone July 03, 2003
 
2.
A wild one. Someone who does not conform to the rest of society. A maverick. A guy who plays by his own rules and to hell with the consequences. Shows you what he can do.
JC - Ladies, let me show you what I can do.

Ladies - Wow. That John Clegg is one loose cannon.
by The Strut October 12, 2004
 
3.
A term of jealous criticism applied to individuals of rare flexibility and creativity, by mobs of petty-minded group-thinking procedure slaves.
They called me a loose cannon until one of my crazy ideas saved them half a million bucks. After that I insisted on being called a 360 degree swivel-mounted artillery unit.
by Alex From Oz October 04, 2007
 
4.
a very irresponsible person who is likely to cause destruction
How did such a loose cannon get into a position of authority?
by The Return of Light Joker August 06, 2008
 
5.
a) (offensive) an irrational/non pragmatic/behaviorally unpredictable person who is neither under the influence of any drugs/alcohol nor has ADD/ADHD
b ) (sarcastic) a person who does rational and somewhat pragmatic things first without, however, having thought them through properly and then asks intelligent questions regarding his previous pragmatic actions
c) an offensive term for children with, or perceived to have, ADD/ADHD, regardless of whether or not this is truly the case
boy a) my girlfriend is such a loose cannon, and makes the most irrational, non-pragmatic decisions, is there anything I can do?

boy b) are you lol, your girlfriend's social worker or psychiatrist? It may be that she is just a loose cannon according to you, IYHO only and normal to everyone else. and lol, is it possible that you are a loose cannon according to her?

boy a) Dunno and idc if i am a loose cannon according to her. IMHO she needs a few doses of methylphenidate
by Sexydimma May 04, 2013
 
6.
1. Reiju Chacko
2. A danger and liability to all surrounding human beings.
After his 3rd cup of double back diamond coffee and 2 red bulls, Reiju Chacko is a loose cannon.
by The White Russian 007 October 21, 2011
 
7.
A drinking game in which the participants consume Haribo fat-free gummy bears before trying to attain the contact information of an attractive member of the opposite gender. Due to the explosive effects that the gummy bears impart on the participants bowels, this means that the attempt to attain information is under a very strict clock. If the participant attains correct information before expelling the contents of his bowels then all of his / her comrades must drink, otherwise he must.
Dude, I totally loose cannoned that girl.

-M.S.
by OtherPseudoname May 16, 2014