νᾶφε καὶ μέμνασο ἀπιστεῖν → keep a clear head and remember not to believe a thing (Epicharmus fr. 250)
deny on oath: P. and V. ἐξομνύναι (or mid.), ἀπομνύναι.
renounce: P. and V. ἐᾶν, χαίρω ἐᾶν, χαίρειν ἐᾶν.