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]

Moby Thesaurus II by Grady Ward, 1.0:

82 Moby Thesaurus words for "chapfallen":
   abashed, afflicted, agitated, ashamed, baffled, balked, beset,
   betrayed, bilked, blasted, blighted, blue, blushing, bothered,
   brooding, broody, cast down, chagrined, confused, crestfallen,
   crossed, crushed, dashed, defeated, dejected, depressed,
   disappointed, discomfited, discomforted, discomposed, disconcerted,
   disconsolate, dished, disillusioned, disquieted, dissatisfied,
   distressed, disturbed, down, down-in-the-mouth, downhearted,
   dumpish, embarrassed, foiled, frustrated, glum, grum, hangdog,
   humbled, humiliated, hung up, ill at ease, ill done-by, ill-served,
   let down, long-faced, moodish, moody, mopey, moping, mopish,
   morose, mortified, mumpish, out of countenance, perturbed, put-out,
   put-upon, red-faced, regretful, shamed, shamefaced, shamefast,
   sorely disappointed, soured, sulky, sullen, thwarted, troubled,
   uncomfortable, uneasy, upset