ῥιζωνυχία
From LSJ
περὶ οὐδὲν γὰρ οὕτως ὑπάρχει τῶν ἀνθρωπίνων ἔργων βεβαιότης ὡς περὶ τὰς ἐνεργείας τὰς κατ' ἀρετήν → since none of man's functions possess the quality of permanence so fully as the activities in conformity with virtue
English (LSJ)
ἡ,
A root of the nail, Poll.2.145 (pl.), cf. Paul.Aeg.6.85:—in Ruf.Onom.85, ῥιζ-νύχια, τά; but -ίαι Id. ap. Orib.25.1.32.
German (Pape)
[Seite 843] ἡ, die Wurzel des Nagels, Medic.; Poll. 2, 145; ῥιζονυχία ist minder gute Schreibart, ῥιζώνυξ, υχος, falsch.