1. verb, slang (of a vehicle) To accelerate or increase speed suddenly or rapidly. Okay, I've got the cash. Now gun it and get us out of here!

2. noun, slang One who has been hired to kill someone. The boss will have a hired gun to take care of the informant, don't worry.

3. noun, slang A particularly muscular arm; an arm's large bicep. Usually used in the plural in reference to both arms or both sets of biceps. He always wears tank tops so he can show off his guns. I caught her flexing her guns in front of the mirror after her workout.

4. noun, slang An important, successful, or influential person. He's the gun at the law firm; he wins every court case he gets. After failing to convince the IT department that implementing new network security controls would be in everyone's best interest, Mike felt it was time to bring in the big guns, so he called a company meeting with the executive board.