προεγγυάομαι
From LSJ
τῶν Λειβηθρίων ἀμουσότερος → more uncultured than Leibethrans, more uncultured than the people of Leibethra, lowest degree of mental cultivation
English (LSJ)
A furnish security or guarantee, Milet.3No.138.42 (iii B.C.):—Pass., App.Fr.1.1.