boner assassin Share definition Flag A person with an appearance or attitude that kills an erection quickly and efficiently, without impunity. "My ex-girlfriend used to be pretty hot back in high school, but now she's a boner assassin." boner assassin by GARY LOVES THE BACON May 13, 2004 0 0 Get merch Get the boner assassin mug. Buy Now — $32.95 See more merch