Now, by Apollo, king, Thou swear'st thy gods in vain.
Shak.
To swear the peace against one, to make oath that one is under the
actual fear of death or bodily harm from the person, in which case the
person must find sureties that he will keep the peace.
Swear"er (?), n. 1. One who swears; one who calls God to witness for
the truth of his declaration.