βῶσαι

From LSJ

κεραυνὸν ἐν γλώττῃ φέρειν → carry a thunderbolt on his tongue

Source

French (Bailly abrégé)

inf. ao. ion. et épq. de βοάω.

Russian (Dvoretsky)

βῶσαι: inf. aor. к βοάω.