The Collaborative International Dictionary of English v.0.48:

Fret \Fret\ (fr[e^]t), v. t. [imp. & p. p. Fretted; p. pr. &
   vb. n. Fretting.] [OE. freten to eat, consume; AS. fretan,
   for foretan; pref. for- + etan to eat; akin to D. vreten,
   OHG. frezzan, G. fressen, Sw. fr[aum]ta, Goth. fra-itan. See
   For, and Eat, v. t.]
   1. To devour. [Obs.]
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            The sow frete the child right in the cradle.
                                                  --Chaucer.
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   2. To rub; to wear away by friction; to chafe; to gall;
      hence, to eat away; to gnaw; as, to fret cloth; to fret a
      piece of gold or other metal; a worm frets the plants of a
      ship.
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            With many a curve my banks I fret.    --Tennyson.
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   3. To impair; to wear away; to diminish.
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            By starts
            His fretted fortunes give him hope and fear. --Shak.
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   4. To make rough, agitate, or disturb; to cause to ripple;
      as, to fret the surface of water.
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   5. To tease; to irritate; to vex.
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            Fret not thyself because of evil doers. --Ps.
                                                  xxxvii. 1.
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Moby Thesaurus II by Grady Ward, 1.0:

106 Moby Thesaurus words for "fretting":
   ablation, ablative, abradant, abrasion, abrasive, annoying, antsy,
   antsy-pantsy, anxiety, anxious, attrition, attritive, bothersome,
   breathless, breathless impatience, buffing, burnishing, chafe,
   chafing, detrition, disquieting, disquietude, distressful,
   distressing, disturbing, dressing, eager, eagerness, edgy, erasure,
   erosion, erosive, excited, excitement, filing, fretful,
   fretfulness, galling, gnawing, grating, grazing, grinding,
   harassing, harassment, haste, hasty, hopped-up, impatience,
   impatient, impatientness, impetuous, impetuousness, in a lather,
   in a stew, in a sweat, irritant, irritating, irritative, lather,
   limation, on edge, plaguing, polishing, rasping, restive,
   restiveness, restless, restlessness, rubbing away, sandblasting,
   sanding, scouring, scrape, scraping, scratch, scratching, scratchy,
   scrub, scrubbing, scuff, shining, smoothing, squirming, squirmy,
   stew, stinging, sweat, tense readiness, torment, tormenting,
   troublesome, uneasiness, uneasy, unpatient, unpatientness, unquiet,
   unquietness, upsetting, wear, wearing away, worriedness,
   worries and cares, worriment, worrisome, worry, worrying