Headword and gloss are both both present middle/passive infinitives. The headword one (from a)gei/rw) is claimed by Latte on Hesychius eta59 as quoted from Homer, Iliad 10.127, where indeed the mss have that reading (also in Apollonius' Homeric Lexicon, Eustathius, and elsewhere); modern editions, though (e.g. Monro & Allen: web address 1), favour the Aristarchan/Aristonican h)gere/qesqai.
This Homeric gloss is paralleled in the Ambrosian Lexicon; it is to be found (according to Adler) in Ambrosianus 12 Sup. 50, and we also have it (headword only) in Laurentianus 59.16 fol.187r.