Source : Webster's Revised Unabridged Dictionary (1913)

Demoralize \De*mor"al*ize\, v. t. [imp. & p. p. {Demoralized};
   p. pr. & vb. n. {Demoralizing}.] [F. d['e]moraliser; pref.
   d['e]- (L. dis- or de) + moraliser. See {Moralize}.]
   To corrupt or undermine in morals; to destroy or lessen the
   effect of moral principles on; to render corrupt or
   untrustworthy in morals, in discipline, in courage, spirit,
   etc.; to weaken in spirit or efficiency.

         The demoralizing example of profligate power and
         prosperous crime.                        --Walsh.

         The vices of the nobility had demoralized the army.
                                                  --Bancroft.

Source : WordNet®

demoralize
     v 1: corrupt morally or by intemperance or sensuality; "debauch
          the young people with wine and women"; "Socrates was
          accused of corrupting young men"; "Do school counselors
          subvert young children?"; "corrupt the morals" [syn: {corrupt},
           {pervert}, {subvert}, {demoralise}, {debauch}, {debase},
           {profane}, {vitiate}, {deprave}, {misdirect}]
     2: lower someone's spirits; make downhearted; "These news
        depressed her"; "The bad state of her child's health
        demoralizes her" [syn: {depress}, {deject}, {cast down}, {get
        down}, {dismay}, {dispirit}, {demoralise}] [ant: {elate}]
     3: confuse or put into disorder; "the boss's behavior
        demoralized everyone in the office"