'well-used' is a modern English compound formed from 'well' + 'used'. 'well' originates from Old English, specifically the word 'wel', where 'wel' meant 'in a good or desirable way'; 'use' (the root of 'used') originates from Latin, via Old French 'user', specifically from Latin 'uti'/'usare', where 'uti'/'usare' meant 'to use'.

'well-used' developed in English by combining the adverb 'well' with the past participle of 'use' (Middle English forms such as 'usen' / 'usyd' derived from Old French 'user', from Latin 'uti'), and by Early Modern English the compound 'well-used' was established with the meaning related to frequent or thorough use.

Initially, the components implied 'used well' or 'used in a good/complete way'; over time the compound came to be used specifically to describe objects or items that are worn or show signs of frequent use (i.e., 'frequently used' or 'worn by use').