'blindworm' originates from Old English, specifically the compound word 'blindwyrm', where 'blind' meant 'unable to see' and 'wyrm' meant 'serpent' or 'worm'.

'blindwyrm' in Old English passed into Middle English as forms like 'blinde worm' or 'blind-worm' and eventually became the modern English 'blindworm' (also seen as 'blind-worm' or conflated with 'slow-worm').

Initially, it meant 'a blind serpent or worm' in a general or mythic sense; over time the meaning narrowed in ordinary usage to denote the specific legless lizard (slow-worm).