θελήμων
From LSJ
ἢ λέγε τι σιγῆς κρεῖττον ἢ σιγὴν ἔχε → either say something better than silence or keep silence (Menander)
English (LSJ)
ον, gen. ονος,
A voluntary, εἰρεσίη A.R.2.557.
German (Pape)
[Seite 1192] ον, freiwillig, Ap. Rh. 2, 557. 4, 1657.
Greek (Liddell-Scott)
θελήμων: -ον, γεν. ονος, θέλων, θεληματικός, Ἀπολλ. Ρόδ. Β. 556.