ἐτυμολόγος
From LSJ
ὁ χρόνος ἐστὶ δάνος, τὸ ζῆν πικρός ἐσθ' ὁ δανίσας → time is a loan, and he who lent you life is a hard creditor | time is on loan and life's lender is a prick
German (Pape)
[Seite 1053] ὁ, der die Etymologie treibt, E. M. u. Schol.
Greek (Liddell-Scott)
ἐτυμολόγος: ον σπουδάζων τὴν ἐτυμολογίαν· ὡς οὐσιαστ., ἐτ., ὁ, ὁ ἐτυμολογῶν, Ἐτυμ. Μ., Varro L. L.