A .45 caliber handgun or pistol, usualy used in urban slang such as rap.
Common to words such as tre deuce being a .32, deuce deuce being a .22.
"Looked up and I seen Swift shootin it out
But I can't see who he's shootin it out with
But Denaun's right behind him squeezin his four fifth"

-Eminem (one shot 2 shot)
by chris November 16, 2004
a .45 handgun

must write 20 letters
must write 20 letters
must write 20 letters
i keep my four fifth tucked in my button up
by thebay707yeeyeeyee! February 26, 2006
i capped yo ass with a four fifth.
by Anonymous October 6, 2003
another word used in place of saying forty five, a colt 45 gun.
man i got in the club with the four fifths, let some shit pop off iam ready.
by bert2 June 30, 2005
noun, slang.

an urban or slang term used to describe a .45 caliber pistol.

origin: southeastern Virginia (Virginia Beach/Norfolk), Newport News
"hit 'em with the neener man/
or that four-fifth guaranteed to lean ya, man, whoa" - Malice of the Clipse, on Baby's "What Happened To That Boy"
by C_Smith May 1, 2006
What Derek Huff will charge as commission to sell a house of a friend because in his words, "that's what gets my dick hard"
Kush: Hey I need to sell my house robey
Robey: Well for you I will only charge four fifths commish because I am currently only at half mast
by J Dog12 March 27, 2009