From Longman Dictionary of Contemporary Englishknackerknack‧er /ˈnækə $ -ər/ verb [transitive] British English spoken informal 1 TIREDto become extremely tired SYN exhaustknacker yourself (out) Slow down – you’ll knacker yourself out!2 → knacker your elbow/hand etcOrigin knacker (1800-1900) knacker “horse-killer”; KNACKERS' YARD
