(obsolete) To seal; to confirm, as by a seal or stamp.
a. 1555, John Bradford, letter to Master Richard Hopkins
He willeth us to eat of the bread […] and drink of that cup all, […] that is, take it as the sacrament of his body and blood […] whereby he doth represent, and to our faith give and obsign unto us, himself wholly, with all the merits and glory of his body and blood.