αὐτοσχεδιαστικός
From LSJ
καὶ ὑποθέμενος κατὰ τῆς κεφαλῆς φέρειν τὰς πληγάς, ὡς ἐν ἐκείνῃ τοῦ τε κακοῦ τοῦ πρὸς ἀνθρώπους → and having instructed them to bring their blows against the head, seeing that the harm to humans ... (Josephus, Antiquities of the Jews 1.50)
English (LSJ)
ή, όν,
A extemporary, Arist.Po.1449a9:—also αὐτοσχεδι-αστός, όν, Alcid.Soph.16,17.