gun
     n 1: a weapon that discharges a missile at high velocity
          (especially from a metal tube or barrel)
     2: large but transportable armament [syn: {artillery}, {heavy
        weapon}, {ordnance}]
     3: a person who shoots a gun (as regards their ability) [syn: {gunman}]
     4: a professional killer who uses a gun [syn: {gunman}, {gunslinger},
         {hired gun}, {gun for hire}, {triggerman}, {hit man}, {hitman},
         {torpedo}, {shooter}]
     5: a hand-operated pump that resembles a gun; forces grease
        into parts of a machine [syn: {grease-gun}]
     6: a pedal that controls the throttle valve; "he stepped on the
        gas" [syn: {accelerator}, {accelerator pedal}, {gas pedal},
         {gas}, {throttle}]
     7: the discharge of a gun as signal or as a salute in military
        ceremonies; "a twenty gun salute"
     v : shoot with a gun
     [also: {gunning}, {gunned}]
Source: WordNet® 2.0

gun vt. [ITS, now rare: from the `:GUN' command] To forcibly terminate
   a program or job (computer, not career). "Some idiot left a background
   process running soaking up half the cycles, so I gunned it." Usage: now
   rare. Compare {can}, {blammo}.


Source: The Jargon File