spark out adjective 1verb 1forms 3 adjective1 •(UK, slang) Completely asleep or unconscious.I steamed in and was promptly knocked spark out by one of them. I came round just in time to see them running for the exit. — 2008 verb1 •(slang) To render unconscious; to knock out."I didn't care if I sparked him out or it went 12 rounds, but people wanted to see him unconscious." — 2017 formssparked out · sparking out · sparks out