gun down

verb3

1. •
   To kill by means of a firearm, especially deliberately and in a brutal manner.

   • When Manzanas arrived home from work, the assailant gunned him down from ambush with a volley of pistol shots and escaped across the nearby border to France. — 1968
2. •
   (figurative) To shoot down; to put an end to.

   • The CEO gunned down that idea before we could present it to the board.
3. •
   (US, slang) To masturbate while making sustained eye contact with someone — typically a female prison officer — as a form of intimidation.