'arthritic' originates from Greek (via New Latin and modern English), specifically from the word 'arthritis' formed from Greek 'arthron' meaning 'joint' and the suffix '-itis' meaning 'inflammation', with the adjectival suffix '-ic' added in English.

'arthritic' changed from the medical noun 'arthritis' (from Late Latin 'arthritēs', from Greek 'arthron' + '-itis') and eventually became the modern English adjective 'arthritic' by adding the suffix '-ic'.

Initially connected to the idea of 'inflammation of a joint', over time the adjective 'arthritic' came to mean 'pertaining to or affected by arthritis; showing the stiffness or pain characteristic of arthritis.'