Definition of knackered

The word "knackered" is a British slang term that means extremely tired or exhausted. Its origin dates back to the early 20th century in the UK. The word is derived from the name of a company called Knackers, which was a firm that specialized in destroying horses or other animals that were no longer fit for work or were too old to continue working. The company's name was pronounced with a distinctive "kna-kered" sound, which over time evolved into "knackered" as a colloquialism to describe someone who has been worn out or exhausted, much like an animal that has been put down. The word gained popularity in the 1950s and 1960s and has since become a common expression in British English to describe someone who is feeling completely exhausted or drained of energy.