Aorist imperative of ἐνέπω , used in the epic formula ἔσπετε νῦν μοι, Μοῦσαι ... "tell me, Muses ..." (four times in the Iliad, e.g. 2.284; also in the Homeric Hymns and Hesiod). Similar glosses in Photius and other lexica.
Probably from *ἔν-σπετε with zero-grade of the root *sekw-; cf. epsilon 1351.