'scabicidal' originates from Modern Latin/English formation, specifically from the Latin word 'scabies' (meaning 'itch') combined with the combining form derived from Latin 'caedere' (through '-cide'/'-cid-') where 'scabies' meant 'itch' and 'caedere' meant 'to kill'.

'scabicidal' changed from the New Latin/English noun 'scabicide' (a substance that kills scabies mites) with the adjectival suffix '-al', and eventually became the modern English adjective 'scabicidal'.

Initially it meant 'relating to scabies' or 'used against scabies', but over time it has come to be used specifically as 'capable of killing the mites that cause scabies'.