What does "gun" mean?

See gun in WNW Idioms

big gun

Slang
  1. an important and influential person
  2. a high-ranking military officer

give it the gun

☆

Etymology: from the resemblance of early airplane accelerators to the trigger of a gun

Slang to cause something to start or gain speed

go great guns

Slang to act with speed and efficiency

gun for

☆
  1. to hunt for with a gun
  2. to look for in order to shoot or harm
  3. Slang to try to get; seek

jump the gun

Informal
  1. to begin a race before the signal has been given
  2. to begin anything before the proper time

spike someone's guns

to frustrate or defeat someone

stick to one's guns

Informal to hold one's position under attack; not withdraw or retreat; be firm

under the gun

Informal in a tense, demanding situation or threatened state, often one involving a deadline

See gun in American Heritage Dictionary 4 Idioms

go great guns

To proceed or perform with great speed, skill, or success.

hold a gun to (someone's) head

To put pressure on someone.

under the gun

Under great pressure or under threat.

Learn more about gun

link/cite print suggestion box