δυσαποκατάστατος
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 hard to restore, M.Ant.11.8, Gal.14.792. II hard to recover from, ὀργαί Phld.Ir.p.63 W.