The Collaborative International Dictionary of English v.0.48:

Pester \Pes"ter\ (p[e^]s"t[~e]r), v. t. [imp. & p. p.
   Pestered; p. pr. & vb. n. Pestering.] [Abbrev. fr.
   impester, fr. OF. empaistrier, empestrer, to entangle the
   feet or legs, to embarrass, F. emp[^e]trer; pref. em-, en-
   (L. in in) + LL. pastorium, pastoria, a fetter by which
   horses are prevented from wandering in the pastures, fr. L.
   pastorius belonging to a herdsman or shepherd, pastor a
   herdsman. See In, and Pasture, Pastor.]
   1. To trouble; to disturb; to annoy; to harass with petty
      vexations.
      [1913 Webster]

            We are pestered with mice and rats.   --Dr. H. More.
      [1913 Webster]

            A multitude of scribblers daily pester the world.
                                                  --Dryden.
      [1913 Webster]

   2. To crowd together in an annoying way; to overcrowd; to
      infest. [Obs.] --Milton.
      [1913 Webster]

            All rivers and pools . . . pestered full with
            fishes.                               --Holland.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

pestered \pestered\ adj.
   Troubled persistently especially with petty annoyances; as,
   the exasperation of a pestered animal.

   Syn: annoyed, harassed, harried.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

pestered
    adj 1: troubled persistently especially with petty annoyances;
           "harassed working mothers"; "a harried expression"; "her
           poor pestered father had to endure her constant
           interruptions"; "the vexed parents of an unruly teenager"
           [syn: annoyed, harassed, harried, pestered,
           vexed]

Moby Thesaurus II by Grady Ward, 1.0:

23 Moby Thesaurus words for "pestered":
   badgered, baited, bedeviled, beset, bugged, bullyragged, chivied,
   deviled, dogged, harassed, harried, heckled, hectored, hounded,
   needled, nipped at, persecuted, picked on, plagued, ragged, teased,
   tormented, worried