'arthritis-free' originates from Modern English, specifically formed as a compound of the noun 'arthritis' and the adjective 'free'.

'arthritis' originates from New Latin 'arthritis', ultimately from Greek 'arthron' meaning 'joint' + the suffix '-itis' meaning 'inflammation'; 'free' originates from Old English 'frēo' and passed through Middle English to modern English as 'free'.

Initially, 'arthritis' meant 'inflammation of a joint' and 'free' meant 'not bound' or 'not affected'; over time the compound came to mean 'not affected by arthritis'.