from Old English forsworen, "perjured," past participle of forswerian "to swear falsely" (see forswear).
Entries linking to forsworn
forswear v.
Old English forswerian "swear falsely" (intransitive), also "abandon or renounce on oath" (transitive), from for- "completely" + swerian "to swear" (see swear (v.)). Related: Forswore; forsworn; forswearing.