The Collaborative International Dictionary of English v.0.48:
Chapfallen \Chap"fall`en\, a. Having the lower chap or jaw drooping, -- an indication of humiliation and dejection; crestfallen; discouraged. See Chopfallen. [1913 Webster]WordNet (r) 3.0 (2006):
chapfallen adj 1: brought low in spirit; "left us fatigued and deflated spiritually" [syn: chapfallen, chopfallen, crestfallen, deflated]