From Middle English atter, ater, from Old English āttor, ǣttor, ātor (“poison”), from Proto-West Germanic *aitr, from Proto-Germanic *aitrą (“gland, matter”), from Proto-Indo-European *h₂eyd-, *h₂oyd- (“tumor, abscess”), related to Ancient Greek οἶδος (oîdos, “swelling, tumour, abscess, produced by internal action”). Cognate with Scots attir (“corrupt matter, pus”), Scots atter, etter (“poison, venom”), Shetlandic eter (“poison; bitter cold”), Old Norse eitr, Icelandic eitur (“poison”), Faroese eitur, Norwegian eiter (“venom”), Swedish etter (“poison, venom, virulence”), Danish edder, ædder (“venom”), Saterland Frisian Atter (“pus”), Dutch etter (“pus”), German Eiter (“poison, pus”).
1
UK, Archaic, Dialectal Poisonous bodily fluid, especially venom of a venomous animal, such as a snake, dragon or other reptile; corrupt or morbid matter from the body, such as pus from a sore or wound; bitter substance, such as bile.
2
Archaic, Figuratively Moral corruption or corruptness; noxious or corrupt influence, poison to the soul, evil, anger, envy, hatred; destruction, death.
From Middle English atter, ater, from Old English āttor, ǣttor, ātor (“poison”), from Proto-West Germanic *aitr, from Proto-Germanic *aitrą (“gland, matter”), from Proto-Indo-European *h₂eyd-, *h₂oyd- (“tumor, abscess”), related to Ancient Greek οἶδος (oîdos, “swelling, tumour, abscess, produced by internal action”). Cognate with Scots attir (“corrupt matter, pus”), Scots atter, etter (“poison, venom”), Shetlandic eter (“poison; bitter cold”), Old Norse eitr, Icelandic eitur (“poison”), Faroese eitur, Norwegian eiter (“venom”), Swedish etter (“poison, venom, virulence”), Danish edder, ædder (“venom”), Saterland Frisian Atter (“pus”), Dutch etter (“pus”), German Eiter (“poison, pus”).