Source : Webster's Revised Unabridged Dictionary (1913)

Atrophy \At"ro*phy\, n. [L. atrophia, Gr. ?; 'a priv. + ? to
   nourish: cf. F. atrophie.]
   A wasting away from want of nourishment; diminution in bulk
   or slow emaciation of the body or of any part. --Milton.

Atrophy \At"ro*phy\, v. t. [p. p. {Atrophied}.]
   To cause to waste away or become abortive; to starve or
   weaken.

Atrophy \At"ro*phy\, v. i.
   To waste away; to dwindle.

Source : WordNet®

atrophy
     n 1: a decrease in size of an organ caused by disease or disuse
          [syn: {wasting}, {wasting away}]
     2: any weakening or degeneration (especially through lack of
        use) [syn: {withering}]
     v : undergo atrophy; "Muscles that are not used will atrophy"
     [also: {atrophied}]