'asthmatic' originates from Greek, specifically the word 'asthma', where 'ásthma' meant 'panting' or 'shortness of breath'.

'asthma' passed into Latin as 'asthma' and then into Old and Middle English (forms like 'astma'/'astema'); the adjective 'asthmatic' was formed in English from the noun 'asthma' with the Greek-derived suffix '-tic' (from '-atikos'), resulting in the modern English word 'asthmatic' and its plural 'asthmatics'.

Initially it referred to 'panting' or 'shortness of breath'; over time it came to denote the medical condition we now call 'asthma' and, by extension, people who have that condition ('asthmatics').