The Collaborative International Dictionary of English v.0.48:

Whit \Whit\, n. [OE. wight, wiht, AS. wiht a creature, a thing.
   See Wight, and cf. Aught, Naught.]
   The smallest part or particle imaginable; a bit; a jot; an
   iota; -- generally used in an adverbial phrase in a negative
   sentence. "Samuel told him every whit." --1 Sam. iii. 18.
   "Every whit as great." --South.
   [1913 Webster]

         So shall I no whit be behind in duty.    --Shak.
   [1913 Webster]

         It does not me a whit displease.         --Cowley.
   [1913 Webster]

WordNet (r) 3.0 (2006):

whit
    n 1: a tiny or scarcely detectable amount [syn: shred,
         scintilla, whit, iota, tittle, smidgen,
         smidgeon, smidgin, smidge]