'crazy' originates from Middle English, specifically the word 'craze,' where 'craze' meant 'to shatter or break.'

'craze' transformed into the adjective 'crazy' in the 16th century, eventually leading to the adverb 'crazily.'

Initially, it meant 'to shatter or break,' but over time it evolved into its current meaning of 'insane or wildly unreasonable.'