look up any word, like cleveland steamer:
 
4.
in chess, a slang term for 'checkmate' not to be confused with taking off ones clothing.
bob: im flashing you!
joe: WHAT?!?!? keep your clothes on!
bob: no, joe. it means checkmate!
joe: oh!
by checkmateflasher March 26, 2009
 
1.
Revealing your "private parts" to another person

ie.
whipping out your penis
showing your tits
Flash me for a dollar
by Mike Truitt June 14, 2003
 
2.
Showing ones semi-boner to females for a thrill.
Wow, look at those babes by the pool. I think I will walk by and flip out my half hard cock and watch their reaction.
by flashboy June 29, 2003
 
3.
Getting angry or aggro and going off on someone, often for no good reason.

LA cats don't seem to know this one, so it must be a Bay thing?
From E-40 song "Flashin'"

"The holiday just came on the first second and third of the month.
Made my check late and i got to fah-lashin on motherfuckers.
Next door neighbor hollerin that shit about my beat too loud
I walked up the motherfuckin steps and i got ta tellin that bitch i'm flashin
Send a rookie to the store to bring me back some rossi rhine
He brought me back chablis, and i get to flashin on that bitch-ass motherfucker, silly nigga
Yknahmsayin? a motherfucker up in this motherfucker flashin.
Get to testin my testicles nigga and i'ma flash on yo' ass."

Urban dictionary wants the complete word in here, so here you go UD: flashing

http://www.youtube.com/watch?v=MiSKFMq1gOo
by Torsky August 25, 2008
 
5.
The procedure of re-programming the flash-memory / Software / computer memory /Read-only memory of an elctronic device
1.I flashed my DVD-ROM yesterday from the flashing utility
2.I need to flash my BIOS since its pretty old
by Aman Y January 13, 2008
 
6.
when someone over reacts to a situation and starts acting crazy or aggressive.
Man...I told john I fucked his girlfriend and he started flashing on me.
by lalalalahh April 24, 2007