δίπτωτος
From LSJ
ψυχῆς πείρατα ἰὼν οὐκ ἂν ἐξεύροιο πᾶσαν ἐπιπορευόμενος ὁδόν· οὕτω βαθὺν λόγον ἔχει → one would never discover the limits of soul, should one traverse every road—so deep a measure does it possess
English (LSJ)
ον,
A having one form for two cases, A.D.Pron. 91.7.
German (Pape)
[Seite 642] mit zwei Casusendungen, Gramm.