Source : Webster's Revised Unabridged Dictionary (1913)

Beset \Be*set"\, v. t. [imp. & p. p. {Beset}; p. pr. & vb. n.
   {Besetting}.] [AS. besettan (akin to OHG. bisazjan, G.
   besetzen, D. bezetten); pref. be- + settan to set. See
   {Set}.]
   1. To set or stud (anything) with ornaments or prominent
      objects.

            A robe of azure beset with drops of gold.
                                                  --Spectator.

            The garden is so beset with all manner of sweet
            shrubs that it perfumes the air.      --Evelyn.

   2. To hem in; to waylay; to surround; to besiege; to
      blockade. ``Beset with foes.'' --Milton.

            Let thy troops beset our gates.       --Addison.

   3. To set upon on all sides; to perplex; to harass; -- said
      of dangers, obstacles, etc. ``Adam, sore beset, replied.''
      --Milton. ``Beset with ills.'' --Addison. ``Incommodities
      which beset old age.'' --Burke.

   4. To occupy; to employ; to use up. [Obs.] --Chaucer.

   Syn: To surround; inclose; environ; hem in; besiege;
        encircle; encompass; embarrass; urge; press.

Besetting \Be*set"ting\, a.
   Habitually attacking, harassing, or pressing upon or about;
   as, a besetting sin.

Source : WordNet®

beset
     v 1: annoy continually or chronically; "He is known to harry his
          staff when he is overworked"; "This man harasses his
          female co-workers" [syn: {harass}, {hassle}, {harry}, {chivy},
           {chivvy}, {chevy}, {chevvy}, {plague}, {molest}, {provoke}]
     2: assail or attack on all sides: "The zebra was beset by
        leopards" [syn: {set upon}]
     3: decorate or cover lavishly with gems [syn: {encrust}, {incrust}]
     [also: {besetting}]

besetting
     See {beset}