δύσθλαστος
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
English (LSJ)
ον,
A hard to crush, tough, Thphr.HP8.4.1 (Comp.), Gal.UP11.17.
German (Pape)
[Seite 681] schwer zu zerbrechen, Theophr.