θαλεῖν
From LSJ
Μεγάλοι δὲ λόγοι μεγάλας πληγὰς τῶν ὑπεραύχων ἀποτίσαντες γήρᾳ τὸ φρονεῖν ἐδίδαξαν → The great words of the arrogant pay the penalty by suffering great blows, and teach one to reason in old age
Greek Monotonic
θᾰλεῖν: απαρ. αορ. βʹ του θάλλω.