ἢ δεῖ σιωπᾶν ἢ λέγειν τὰ καίρια → you should either keep silence or make timely remarks (Menander)
adj.
P. and V. ἀπόπληκτος, μανιώδης, Ar. and P. παράπληξ, μανικός, V. ἐμμανής (Plat. also but rare P.), Ar. and V. παραπεπληγμένος; see mad.
