Source : Webster's Revised Unabridged Dictionary (1913)

Retrogress \Re"tro*gress\, n. [Cf. L. retrogressus.]
   Retrogression. [R.] --H. Spenser.

Source : WordNet®

retrogress
     v 1: get worse; fall back to a previous or worse condition [syn:
          {regress}, {retrograde}] [ant: {progress}]
     2: go back to bad behavior; "Those who recidivate are often
        minor criminals" [syn: {relapse}, {lapse}, {recidivate}, {regress},
         {fall back}]