'asperate' originates from Latin, specifically the verb 'asperare', where 'asper' meant 'rough'.

'asperate' came into English via Medieval/Late Latin forms such as 'asperatus' (past participle of 'asperare') and was adopted into English with the sense related to roughening or irritating.

Initially, it meant 'to make rough' (literally to make something 'asper'); over time the meaning broadened to include 'to irritate' in both physical and figurative senses.