'miasmatic' originates from Greek via New Latin/English, specifically from the Greek word 'miasma', where 'miasma' meant 'stain' or 'pollution'.

'miasmatic' developed from the noun 'miasma' (Greek 'miasma') with the adjectival suffix '-atic' in Modern English; the term appears in English in contexts describing noxious vapors and, historically, medical theory.

Initially it referred to actual 'polluting' vapours or the concept of pollution ('stain'/'pollution'); over time it has retained that sense and also acquired figurative uses describing an oppressive, corrupt, or noxious atmosphere.