Comparable entry, according to Adler, in the Ambrosian Lexicon (1698).
The headword is first-person singular, present indicative active, of the verb e)peisxe/w -- and as such perhaps merely paradigmatic rather than actually quoted in that form from anywhere.
The verb is unattested in literature before the first century CE, and this particular form is unattested in previous literature (though it appears later in Nicetas Choniates, Oration 15 p. 167.17).
cf. generally chi 197.