[1] The headword is future passive, third person singular, from the root *ghwn- (qei/nw, e)/pefnon). Same gloss in the Ambrosian Lexicon (according to Adler), ps.-Zonaras, and a scholion on Homer, Iliad 15.140, where this form occurs (web address 1).
[2] Epic future of fei/domai, third person singular; cf. Etymologicum Magnum 667.20 and a scholion on Homer, Iliad 15.215, where this form occurs (web address 2).