'decrepit' originates from Latin, specifically the word 'decrepitus,' where 'de-' meant 'down' and 'crepitus' meant 'rattling or creaking.'

'decrepitus' transformed into the Old French word 'decrepit,' and eventually became the modern English word 'decrepit' through Middle English.

Initially, it meant 'rattling or creaking due to age,' but over time it evolved into its current meaning of 'worn out or ruined because of age or neglect.'