προεγγυάομαι
From LSJ
χρώμεθα γὰρ πολιτείᾳ οὐ ζηλούσῃ τοὺς τῶν πέλας νόμους → we live under a form of government which does not emulate the institutions of our neighbours
English (LSJ)
furnish security or guarantee, Milet.3No.138.42 (iii B.C.):—Pass., App.Fr.1.1.