LSJ
Pass., (ἰός³) become or be rusty, Arist. Col. 793b6, Thphr. Char. 10.14, Dsc. 5.78, Antig. Mir. 151.
become acrid, embittered, Hsch. ; — Act. ἰόω, only late, rust, ὁ σίδηρος μᾶλλον ἰοῖ Olymp. in Mete. 266.26, cf. 270.14; convert into ἰός, Zos.Alch. pp. 148, 238B.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)