Longman Dictionary of Contemporary English - gun

~1 n 1 a weapon from which bullets or shells1 (3) are fired 2 a tool used to send out a liquid, such as paint, grease1 (2), or glue, by pressure  (- see also flashgun, spray gun) 3 AmE informal someone who is temporarily put in a position to do a particular job  (He was the sixth gun on the job.) 4 hired gun AmE informal someone who is paid to shoot someone else  (- see also son of a gun, stick to your guns stick1, jump the gun jump1 (11), go great guns great (7), spike sb's guns spike2 (4)) ~2 v 1 AmE informal to make the engine of a car go very fast by pressing the accelerator (1) very hard  (gun it (=make a car go fast)) 2 be gunning for sb BrE informal to be trying to find an opportunity to criticize or harm someone  (Ever since I proved he'd made a mistake in the accounts he's been gunning for me.) gun sb down phr v to shoot someone and badly injure or kill them, especially someone who cannot defend themselves  (Innocent civilians were gunned down in the street.)