The Collaborative International Dictionary of English v.0.48:

Fit \Fit\, a. [Compar. Fitter (f[i^]t"t[~e]r); superl.
   Fittest (f[i^]t"t[e^]st).] [OE. fit, fyt; cf. E. feat neat,
   elegant, well made, or icel. fitja to web, knit, OD. vitten
   to suit, square, Goth. f[=e]tjan to adorn. [root]77.]
   1. Adapted to an end, object, or design; suitable by nature
      or by art; suited by character, qualities, circumstances,
      education, etc.; qualified; competent; worthy.
      [1913 Webster]

            That which ordinary men are fit for, I am qualified
            in.                                   --Shak.
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            Fit audience find, though few.        --Milton.
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   2. Prepared; ready. [Obs.]
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            So fit to shoot, she singled forth among
            her foes who first her quarry's strength should
            feel.                                 --Fairfax.
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   3. Conformed to a standart of duty, properiety, or taste;
      convenient; meet; becoming; proper.
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            Is it fit to say a king, Thou art wicked? --Job
                                                  xxxiv. 18.

   Syn: Suitable; proper; appropriate; meet; becoming;
        expedient; congruous; correspondent; apposite; apt;
        adapted; prepared; qualified; competent; adequate.
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The Collaborative International Dictionary of English v.0.48:

Fitter \Fit"ter\, n.
   1. One who fits or makes to fit; esp.:
      (a) One who tries on, and adjusts, articles of dress.
      (b) One who fits or adjusts the different parts of
          machinery to each other.
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   2. A coal broker who conducts the sales between the owner of
      a coal pit and the shipper. [Eng.] --Simmonds.
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The Collaborative International Dictionary of English v.0.48:

Fitter \Fit"ter\, n.
   A little piece; a flitter; a flinder. [Obs.]
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         Where's the Frenchman? Alas, he's all fitters. --Beau.
                                                  & Fl.
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WordNet (r) 3.0 (2006):

fitter
    adj 1: improved in health or physical condition [syn: fitter,
           healthier]
    n 1: someone who fits a garment to a particular person