ἀπρόσοδος
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)
ον,
A without approach, inaccessible, βίος Phryn.Com. 18; ὄρη Procop.Goth.4.16. II not yielding a return, unproductive, Phld. Oec.p.35J.