The headword is a two-termination adjective, glossed here as feminine accusative singular. There are very similar entries, but for the neuter singular, in other lexica; they include Timaeus' Platonic Lexicon s.v., probably generated by Plato, Critias 111A. The Suda's feminine might be a simple mistake, but if so it was not corrected by ps.-Zonaras (who converts everything into the nominative case, under the headword eu)/botos gh=); and suitable feminines can be found in e.g. Plutarch, Alexander 59.1 (on the Indian moira of Taxiles/Omphis).