διεγγυᾶν
From LSJ
εἰργάζοντο λογάδην φέροντες λίθους καὶ ξυνετίθεσαν ὡς ἕκαστόν τι ξυμβαίνοι → they went to work bringing the stones as they picked them out and put them together as each one happened to fit
Greek > English (Woodhouse Verbs Reversed)
give security for a person, offer bail for (see also: διεγγυῶ, διεγγυάω)