δυσδιάγνωστος
From LSJ
οὗτος ἐγὼ ταχυτᾶτι· χεῖρες δὲ καὶ ἦτορ ἴσο → this is my speed: my hands and heart are its equal, such am I for speed; my hands and heart are just as good
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.