κρήμνη

From LSJ

ἢ λέγε τι σιγῆς κρεῖττον ἢ σιγὴν ἔχε → either say something better than silence or keep silence (Menander)

Source

Russian (Dvoretsky)

κρήμνη: Eur. 2 л. sing. imper. к κρήμνημι.