The Collaborative International Dictionary of English v.0.48:

Somewhat \Some"what`\, adv.
   In some degree or measure; a little.
   [1913 Webster]

         His giantship is gone, somewhat crestfallen. --Milton.
   [1913 Webster]

         Somewhat back from the village street.   --Longfellow.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Somewhat \Some"what`\, n.
   1. More or less; a certain quantity or degree; a part, more
      or less; something.
      [1913 Webster]

            These salts have somewhat of a nitrous taste.
                                                  --Grew.
      [1913 Webster]

            Somewhat of his good sense will suffer, in this
            transfusion, and much of the beauty of his thoughts
            will be lost.                         --Dryden.
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   2. A person or thing of importance; a somebody.
      [1913 Webster]

            Here come those that worship me.
            They think that I am somewhat.        --Tennyson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

somewhat
    adv 1: to a small degree or extent; "his arguments were somewhat
           self-contradictory"; "the children argued because one
           slice of cake was slightly larger than the other" [syn:
           slightly, somewhat, more or less]
    2: to a moderately sufficient extent or degree; "pretty big";
       "pretty bad"; "jolly decent of him"; "the shoes are priced
       reasonably"; "he is fairly clever with computers" [syn:
       reasonably, moderately, pretty, jolly, somewhat,
       fairly, middling, passably] [ant: immoderately,
       unreasonably]

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "somewhat":
   a bit, a little, adequately, after a fashion, any, anything,
   appreciably, at any rate, at best, at least, at most, at the least,
   at the most, at the outside, at worst, aught, comparatively,
   considerably, detectably, extremely, fairly, far, in a manner,
   in a measure, in a way, in part, in some measure, incompletely,
   insignificantly, kind of, leastwise, merely, mildly, moderately,
   modestly, more or less, not comprehensively, not exhaustively,
   only, part, partially, partly, pretty, pro tanto, purely, quite,
   rather, relatively, scarcely, significantly, simply, slightly,
   so far, some, something, sort of, thus far, to a degree,
   to some degree, to some extent, tolerably, very, visibly