The Collaborative International Dictionary of English v.0.48:

Backsliding \Back"slid"ing\, n.
   The act of one who backslides; abandonment of faith or duty.
   [1913 Webster]

         Our backslidings are many.               --Jer. xiv. 7.
   [1913 Webster] backspace

The Collaborative International Dictionary of English v.0.48:

Backslide \Back"slide"\ (b[a^]k"sl[imac]d"; 277), v. i. [imp.
   Backslid; p. p. Backslidden, Backslid; p. pr. & vb. n.
   Backsliding.] [Back, adv. + slide.]
   To slide back; to fall away; esp. to abandon gradually the
   faith and practice of a religion that has been professed.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Backsliding \Back"slid"ing\, a.
   Slipping back; falling back into sin or error; sinning.
   [1913 Webster]

         Turn, O backsliding children, saith the Lord. --Jer.
                                                  iii. 14.
   [1913 Webster]

WordNet (r) 3.0 (2006):

backsliding
    n 1: a failure to maintain a higher state [syn: backsliding,
         lapse, lapsing, relapse, relapsing, reversion,
         reverting]