δυσδιάγνωστος
From LSJ
Χρὴ τῶν ἀγαθῶν διακναιομένων πενθεῖν ὅστις χρηστὸς ἀπ' ἀρχῆς νενόμισται → When a good man is hurt, all who would be called good must suffer with him
English (LSJ)
ον,
A hard to distinguish, Cic.Att.5.4.1, D.H.2.71, Gal.9.433, etc.
German (Pape)
[Seite 677] schwer zu unterscheiden, Dion. Hal. 2, 71.