Source : Webster's Revised Unabridged Dictionary (1913)

Unwind \Un*wind"\, v. t. [AS. unwindan. See 1st {Un-}, and
   {Wind} to coil.]
   1. To wind off; to loose or separate, as what or convolved;
      to untwist; to untwine; as, to unwind thread; to unwind a
      ball of yarn.

   2. To disentangle. [Obs.] --Hooker.

Unwind \Un*wind"\, v. i.
   To be or become unwound; to be capable of being unwound or
   untwisted.

Source : WordNet®

unwind
     v 1: reverse the winding or twisting of; "unwind a ball of yarn"
          [syn: {wind off}, {unroll}] [ant: {wind}]
     2: separate the tangles of [syn: {disentangle}]
     3: become less tense, rest, or take one's ease; "He relaxed in
        the hot tub"; "Let's all relax after a hard day's work"
        [syn: {relax}, {loosen up}, {unbend}, {decompress}, {slow
        down}] [ant: {tense}]
     4: cause to feel relaxed; "A hot bath always relaxes me" [syn:
        {relax}, {unstrain}, {unlax}, {loosen up}, {make relaxed}]
        [ant: {tense}, {tense}]
     [also: {unwound}]