to pursue with harassing or oppressive treatment, especially because of religion, race, or beliefs; harass persistently.
2.
to annoy or trouble persistently.
Origin: 1400–50; late Middle English; back formation from persecutour persecutor ≪ Late Latin persecūtor orig. prosecutor, equivalent to persecū-, variant stem of persequī to prosecute, pursue closely (see per-, sequence) + -tor-tor