look up any word, like cleveland steamer:
 
1.
The name of a fictional person, which is used for the reason that you are doing something. Used in place of "just in case".
bob: can you pack an extra sleeping bag?
mary: why? we have enough...
bob: for Justin.
mary: who?
bob: Justin Case.

or

Jack: just chuckin in a few extra beers for Justin...
by Jackson Beavis January 03, 2008
 
2.
A backup, ie. refering to a person as the justification for doing something.
This copy is for Justin Case.
by jc.black April 23, 2007
 
3.
A suitcase of spare clothes in case your trip is extended or the weather changes drastically.
Since we are headed for Florida and the weather's been crazy I have this suitcase of warm weather clothes and this justincase filled will cooler weather clothes.
by rubinator December 17, 2010
 
4.
to be the back up guy/girl when dating someone
Dude, you remember that chick I went out with last week?
I'm pretty sure that whore already has a boyfriend. I think I'm her Justin Case guy if they break up.
by Beefcake305 February 08, 2011
 
5.
1 address.
2 condom.
He gave me a sweet kiss on the cheek as he left and handed me his "just in case".
by 69jiji November 01, 2006