The Collaborative International Dictionary of English v.0.48:

Persecute \Per"se*cute\, v. t. [imp. & p. p. Persecuted; p.
   pr. & vb. n. Persecuting.] [F. pers['e]cueter, L. persequi,
   persecutus, to pursue, prosecute; per + sequi to follow,
   pursue. See Per-, and Second.]
   1. To pursue in a manner to injure, grieve, or afflict; to
      beset with cruelty or malignity; to harass; especially, to
      afflict, harass, punish, or put to death, for adherence to
      a particular religious creed or mode of worship.
      [1913 Webster]

            Do good to them that hate you, and pray for them
            which despitefully use you, and persecute you.
                                                  --Matt. v. 44.
      [1913 Webster]

   2. To harass with importunity; to pursue with persistent
      solicitations; to annoy. --Johnson.
      [1913 Webster]

   Syn: To oppress; harass; distress; worry; annoy.
        [1913 Webster]

WordNet (r) 3.0 (2006):

persecute
    v 1: cause to suffer; "Jews were persecuted in the former Soviet
         Union" [syn: persecute, oppress]