swear the peace verb1 •(historical) To swear legally (against someone) that one is in fear of physical violence from a person, in order that they be put under bond to keep the peace.He […] told me he despised my threats; I had no resource; I could not swear the peace against him!—I was not afraid of my life!—he had never struck me! — 1798 formsswore the peace · sworn the peace · swearing the peace · swears the peace