Source : Webster's Revised Unabridged Dictionary (1913)

Chapfallen \Chap"fall`en\, a.
   Having the lower chap or jaw drooping, -- an indication of
   humiliation and dejection; crestfallen; discouraged. See
   {Chopfallen}.

Source : WordNet®

chapfallen
     adj : brought low in spirit; "left us fatigued and deflated
           spiritually" [syn: {chopfallen}, {crestfallen}, {deflated}]