προσέχειν τὸν νοῦν
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 > English (Woodhouse)
heed, mark, note, notice, apply one's mind to, attend to, bestow attention, pay attention to, pay attention