προεγγυάομαι
From LSJ
κακοὶ μάρτυρες ἀνθρώποισιν ὀφθαλμοὶ καὶ ὦτα βαρβάρους ψυχὰς ἐχόντων → eyes and ears are poor witnesses for men if their souls do not understand the language (Heraclitus Phil.: Fr. B 107; Testimonia: Fragment 16, line 6)
English (LSJ)
A furnish security or guarantee, Milet.3No.138.42 (iii B.C.):—Pass., App.Fr.1.1.
