The Collaborative International Dictionary of English v.0.48:

Worry \Wor"ry\, v. t. [imp. & p. p. Worried; p. pr. & vb. n.
   Worrying.] [OE. worowen, wirien, to strangle, AS. wyrgan in
   [=a]wyrgan; akin to D. worgen, wurgen, to strangle, OHG.
   wurgen, G. w["u]rgen, Lith. verszti, and perhaps to E.
   wring.]
   [1913 Webster]
   1. To harass by pursuit and barking; to attack repeatedly;
      also, to tear or mangle with the teeth.
      [1913 Webster]

            A hellhound that doth hunt us all to death;
            That dog that had his teeth before his eyes,
            To worry lambs and lap their gentle blood. --Shak.
      [1913 Webster]

   2. To harass or beset with importunity, or with care an
      anxiety; to vex; to annoy; to torment; to tease; to fret;
      to trouble; to plague. "A church worried with
      reformation." --South.
      [1913 Webster]

            Let them rail,
            And worry one another at their pleasure. --Rowe.
      [1913 Webster]

            Worry him out till he gives consent.  --Swift.
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   3. To harass with labor; to fatigue. [Colloq.]
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The Collaborative International Dictionary of English v.0.48:

Worry \Wor"ry\, v. i.
   To feel or express undue care and anxiety; to manifest
   disquietude or pain; to be fretful; to chafe; as, the child
   worries; the horse worries.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Worry \Wor"ry\, n.; pl. Worries.
   A state of undue solicitude; a state of disturbance from care
   and anxiety; vexation; anxiety; fret; as, to be in a worry.
   "The whir and worry of spindle and of loom." --Sir T. Browne.
   [1913 Webster]

WordNet (r) 3.0 (2006):

worry
    n 1: something or someone that causes anxiety; a source of
         unhappiness; "New York traffic is a constant concern";
         "it's a major worry" [syn: concern, worry, headache,
         vexation]
    2: a strong feeling of anxiety; "his worry over the prospect of
       being fired"; "it is not work but worry that kills"; "he
       wanted to die and end his troubles" [syn: worry, trouble]
    v 1: be worried, concerned, anxious, troubled, or uneasy; "I
         worry about my job"
    2: be concerned with; "I worry about my grades" [syn: worry,
       care]
    3: disturb the peace of mind of; afflict with mental agitation
       or distress; "I cannot sleep--my daughter's health is
       worrying me" [syn: worry, vex] [ant: assure,
       reassure]
    4: be on the mind of; "I worry about the second Germanic
       consonant shift" [syn: concern, interest, occupy,
       worry]
    5: lacerate by biting; "the dog worried his bone"
    6: touch or rub constantly; "The old man worried his beads"