impostume
/ɪmˈpɒstjuːm
/(also imposthume)
noun archaic
A swelling containing pus; an abscess: an impostume in his breast the patient was dangerously ill of an imposthume
Origin
Late Middle English: from Old French empostume, alteration of apostume, from Latin and Greek apostema 'separation of pus into an abscess', from Greek apostēnai 'withdraw'.