1) a firearm chambered for the .45 ACP cartridge (usually a large frame semi-automatic) or the ammunition for same.
2) phonograph record or player with 45 RPM spindle speed.
3) (archaic) a firearm chambered for the .45 Colt cartridge (commonly a single-action revolver, as seen in western movies)
by Aantgray February 13, 2003
Get the 45 mug.
A back handed slap in the face using 4 fingers followed by an open handed 5 finger slap in the opposite direction.
Dude you're pissing me off! Shut up before I 45 ya!
by Sambiase March 27, 2015
Get the 45 mug.
1) A Crazy Person (Derived from police code)

2) A Hooligan
Requesting backup, there is a 45 at the playground threatening people

Look at that 45 vapeing over there
by Szechuan October 13, 2017
Get the 45 mug.
Pull out of a curbed driveway with a 45 degree angle so as to not hit the front bumper on the sidewalk.
Dude! You'd better 45 it or else your bumper's gonna get some major pwnage.
Get the 45 it mug.
.45 is the caliber, in inches, not mm. a 45mm gun is fucking huge.
Whoever thought a .45 is a 45mm is a moron.
by Anonymous February 12, 2003
Get the 45 mug.
Verb describing the action of "grabbing her by the pussy" at a 45 degree angle in honor of our 45 president trump himself
Bro go give her the 45 and shell definitely come home with you!
by Tuna584 March 31, 2019
Get the The 45 mug.
1: A .45 caliber Firearm, usually a handgun.

2: A song written by Shinedown, with arguable many meanings but most certainly not about a breakup. many believe the song is about conformity and the dangers and sorrow of our shallow society.
"Yo nigga i bust you with my .45"

"send away for a priceless gift, one not suttle, one not o nt he list..."
by Pumba December 18, 2004
Get the .45 mug.