gun down

verb

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.”
To shoot down; to put an end to.
“The CEO gunned down that idea before we could present it to the board.”
To masturbate while making sustained eye contact with someone — typically a female prison officer — as a form of intimidation.
“In the cell diagonally across from mine, a prisoner regularly “gunned down” the nurse on her morning rounds. He deliberately masturbated so that she'd see him through the cell door window as he ejaculated.”