intransitive. With for (in Old English also †fore). To speak or make a statement or commitment on behalf of; to undertake responsibility on behalf of.

spec. To lift (a child) from the font (formerly the duty of a sponsor at baptism); to stand sponsor to; hence transferred to baptize, christen. Obs…

to fang to: to be sponsor for. dial.

transitive. To be a gossip or sponsor to; to give a name to. Obsolete.