στερρόνους
From LSJ
ὃν οὐ τύπτει λόγος οὐδὲ ῥάβδος → if words don't get through, neither a beating will | if the carrot doesn't work, the stick will not work either | whom words do not strike, neither does the rod
English (LSJ)
ουν,
A hard-, stern-minded, Tz. ad Hes.Op.129 (Comp.).
Greek (Liddell-Scott)
στερρόνους: ουν, ὁ ἔχων στερεὸν (γερόν), αὐστηρὸν νοῦν, Τζέτζ. εἰς Ἡσ. Ἔργ. κ. Ἡμ. 129.