The headword is aorist indicative active, third person plural, of e)pikhru/ssw (cf. epsilon 2360). It might be extracted from the first quotation given here, though there are extant alternatives in (e.g.) Herodotus and Polybius.
[1] Quotation unidentifiable (Adler suggests Aelian), via the Excerpta of Constantine Porphyrogenitus. Such proclamations of reward using forms of the headword are not uncommon. Adler cites the case of Diagoras at delta 524 (and Ammonius 184), but there is also Plutarch, Themistocles 29, as well as Lysias 6.18 (a closer parallel than any of the others).
[2] Quotation (already at alpha 2729) unidentifiable. Adler also cites the Ambrosian Lexicon (2316, 2318). This quotation uses a form of a verb, khrukeu/omai, that is different from, though related to, the headword. This verb is also glossed in the next entry, epsilon 2038, and it is possible that this quotation was meant for that entry.