Source : Webster's Revised Unabridged Dictionary (1913)

Pester \Pes"ter\, 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.

            We are pestered with mice and rats.   --Dr. H. More.

            A multitude of scribblers daily pester the world.
                                                  --Dryden.

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

            All rivers and pools . . . pestered full with
            fishes.                               --Holland.

Source : WordNet®

pestering
     adj : causing irritation or annoyance; "tapping an annoying rhythm
           on his glass with his fork"; "aircraft noise is
           particularly bothersome near the airport"; "found it
           galling to have to ask permission"; "an irritating
           delay"; "nettlesome paperwork"; "a pesky mosquito";
           "swarms of pestering gnats"; "a plaguey newfangled
           safety catch"; "a teasing and persistent thought
           annoyed him"; "a vexatious child"; "it is vexing to
           have to admit you are wrong" [syn: {annoying}, {bothersome},
            {galling}, {irritating}, {nettlesome}, {pesky}, {pestiferous},
            {plaguy}, {plaguey}, {teasing}, {vexatious}, {vexing}]