extemporise
From LSJ
οὐ βούλομαι δυσχερὲς εἰπεῖν οὐδὲν ἀρχόμενος τοῦ λόγου, οὗτος δ' ἐκ περιουσίας μου κατηγορεῖ → for me—but I wish to say nothing untoward at the beginning of my speech—whereas he prosecutes me from a position of advantage | but for me—I do not wish to say anything harsh at the beginning of the speech, but he prosecutes me from a position of strength
