From Longman Dictionary of Contemporary Englishconkconk1 /kɒŋk $ kɑːŋk, kɒːŋk/ noun [countable] British English informal HBHa noseconkconk2 verb [transitive] informalHIT to hit someone hard, especially on the head → conk out→ See Verb table
Examples from the Corpus
conk• They came, they saw, they got conked.• His 62-year-old converted trawler conked out after leaving Newfoundland on the return leg.• I finally conked out at around four, in the middle of a Twilight Zone rerun.Origin conk2 (1800-1900) → CONK2; conk out (1900-2000) Origin unknown 