to smash, break, wipe out, beat, hurt, etc.

Used mostly by surfers
Surfer 1: I was gettin shacked on that 20-foot monster, and that kook cut me off and made me break my board.

Surfer 2: Dude what'd you do to him?

Surfer 1: I dempskied the kooks board over his motha fuckin' head.
by Rich June 23, 2006
Get the Dempski mug.