Similar entry already in Hesychius epsilon7379 (and cf. Pollux 4.25). The headword is imperfect, third person plural (or, less probably, first person singular), of fenaki/zw (LSJ entry at web address 1). In general this verb is common in the Attic orators, especially Demosthenes, and in comedy, though this particular form is extant only in post-classical writers.
The Suda's gloss is the same form of a)pata/w; cf. phi 194, phi 196.