Perseus analyses of ἐπηπείλησ':

1. ἐπηπείλησα,ἐπαπειλέω (hold out as a threat to): aor ind act 1st sg (attic epic ionic)
2. ἐπηπείλησο,ἐπαπειλέω (hold out as a threat to): plup ind mp 2nd sg (attic epic doric ionic aeolic)
3. ἐπηπείλησο,ἐπαπειλέω (hold out as a threat to): perf imperat mp 2nd sg (attic epic doric ionic aeolic)
4. ἐπηπείλησε,ἐπαπειλέω (hold out as a threat to): aor ind act 3rd sg (attic epic ionic)
5. ἐπηπείλησαι,ἐπαπειλέω (hold out as a threat to): perf ind mp 2nd sg (attic epic doric ionic aeolic)

LSJ entry

ἐπᾰπειλέω