ἀγνωστί
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)
Adv. A secretly, unperceived, Ps.-Callisth.3.19.
Spanish (DGE)
adv. secretamente, a escondidas Ps.Callisth.116.23, Choerob. en Theodos.Gr.Sp.231 (ἀγνωϊστί cód.).