The Collaborative International Dictionary of English v.0.48:

Atrophy \At"ro*phy\, v. i.
   To waste away; to dwindle.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Atrophy \At"ro*phy\, n. [L. atrophia, Gr. ?; 'a priv. + ? to
   nourish: cf. F. atrophie.]
   A wasting away from lack of nourishment; diminution in bulk
   or slow emaciation of the body or of any part. --Milton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Atrophy \At"ro*phy\, v. t. [p. p. Atrophied.]
   To cause to waste away or become abortive; to starve or
   weaken.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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