λιγύμοχθος
From LSJ
ἐν δὲ τοῖς φυσικοῖς ἀεὶ οὕτως, ἂν μή τι ἐμποδίσῃ → in natural products the sequence is invariable, if there is no impediment | now with that which is natural it is always thus if there is no impediment
German (Pape)
[Seite 43] sich mit hellem Gesange abmühend, ἀηδών, Ar. Av. 1381, v. l. λιγύμυθος.
Russian (Dvoretsky)
λιγύμοχθος: без устали и звонко поющий (Arph. - v. l. λιγύφθογγος).