The Collaborative International Dictionary of English v.0.48:

Wince \Wince\, v. i. [imp. & p. p. Winced; p. pr. & vb. n.
   Wincing.] [OE. wincen, winchen, OF. quencir, guenchir,
   guenchier, giencier, guinchier, and (assumed) winchier,
   winchir, to give way, to turn aside, fr. OHG. wankjan,
   wenken, to give way, to waver, fr. winchan to turn aside, to
   nod, akin to E. wink. See Wink.]
   [1913 Webster]
   1. To shrink, as from a blow, or from pain; to flinch; to
      start back.
      [1913 Webster]

            I will not stir, nor wince, nor speak a word.
                                                  --Shak.
      [1913 Webster]

   2. To kick or flounce when unsteady, or impatient at a rider;
      as, a horse winces.
      [1913 Webster]