The Collaborative International Dictionary of English v.0.48:

Retrograde \Re"tro*grade\, a. [L. retrogradus, from retrogradi,
   retrogressus, to retrograde; retro back + gradi to step: cf.
   F. r['e]trograde. See Grade.]
   1. (Astron.) Apparently moving backward, and contrary to the
      succession of the signs, that is, from east to west, as a
      planet. --Hutton.
      [1913 Webster]

            And if he be in the west side in that condition,
            then is he retrograde.                --Chaucer.
      [1913 Webster]

   2. Tending or moving backward; having a backward course;
      contrary; as, a retrograde motion; -- opposed to
      progressive. "Progressive and not retrograde." --Bacon.
      [1913 Webster]

            It is most retrograde to our desire.  --Shak.
      [1913 Webster]

   3. Declining from a better to a worse state; as, a retrograde
      people; retrograde ideas, morals, etc. --Bacon.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Retrograde \Re"tro*grade\, v. i. [imp. & p. p. Retrograded; p.
   pr. & vb. n. Retrograding.] [L. retrogradare, retrogradi:
   cf. F. r['e]trograder.]
   1. To go in a retrograde direction; to move, or appear to
      move, backward, as a planet.
      [1913 Webster]

   2. Hence, to decline from a better to a worse condition, as
      in morals or intelligence.
      [1913 Webster]

WordNet (r) 3.0 (2006):

retrograde
    adj 1: moving from east to west on the celestial sphere; or--for
           planets--around the sun in a direction opposite to that
           of the Earth [ant: direct]
    2: of amnesia; affecting time immediately preceding trauma [ant:
       anterograde]
    3: going from better to worse [syn: retrograde,
       retrogressive]
    4: moving or directed or tending in a backward direction or
       contrary to a previous direction [syn: retral,
       retrograde]
    v 1: move backward in an orbit, of celestial bodies
    2: move in a direction contrary to the usual one; "retrograding
       planets"
    3: move back; "The glacier retrogrades" [syn: retrograde,
       retreat]
    4: go back over; "retrograde arguments" [syn: retrograde,
       rehash, hash over]
    5: get worse or fall back to a previous condition [syn:
       regress, retrograde, retrogress] [ant: advance, come
       along, come on, get along, get on, progress, shape
       up]

Moby Thesaurus II by Grady Ward, 1.0:

109 Moby Thesaurus words for "retrograde":
   aft, after, aftermost, atavistic, back, backslide, backward, cock,
   coming apart, cracking, crumbling, decadent, decline, declining,
   degenerate, descend, deteriorate, deteriorating, disimprove,
   disintegrate, disintegrating, draining, drooping, dwindling,
   ebbing, effete, fading, failing, fall astern, fall back,
   fall behind, falling, flagging, fragmenting, get behind, get worse,
   go backwards, go behind, going to pieces, grow worse, hind, hinder,
   hindermost, hindhand, hindmost, invert, jerk back, languishing,
   lapse, lapse back, let down, lose ground, marcescent, pining,
   posterior, postern, pull back, reactionary, rear, rearmost,
   rearward, recede, recessive, recidivate, recidivist, recidivous,
   regress, regressive, relapse, retract, retral, retreat,
   retroactive, retrocede, retrocessive, retroflex, retrogress,
   retrogressive, retrorse, retroverse, retrovert, return, returnable,
   reverse, reversible, reversional, reversionary, revert, revertible,
   revulsionary, rot, shriveling, sicken, sink, sinking, slacken,
   sliding, slip back, slipping, slumping, subsiding, tabetic, tail,
   waning, wasting, wilting, withering, worsen, worsening