The Collaborative International Dictionary of English v.0.48:

Encourage \En*cour"age\ (?; 48), v. t. [imp. & p. p.
   Encouraged (?; 48); p. pr. & vb. n. Encouraging.] [F.
   encourager; pref. en- (L. in) + courage courage. See
   Courage.]
   To give courage to; to inspire with courage, spirit, or hope;
   to raise, or to increase, the confidence of; to animate;
   enhearten; to incite; to help forward; -- the opposite of
   discourage.
   [1913 Webster]

         David encouraged himself in the Lord.    --1 Sam. xxx.
                                                  6.

   Syn: To embolden; inspirit; animate; enhearten; hearten;
        incite; cheer; urge; impel; stimulate; instigate;
        countenance; comfort; promote; advance; forward;
        strengthen.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Encouraging \En*cour"a*ging\, a.
   Furnishing ground to hope; inspiriting; favoring. --
   En*cour"a*ging*ly, adv.
   [1913 Webster]

WordNet (r) 3.0 (2006):

encouraging
    adj 1: giving courage or confidence or hope; "encouraging
           advances in medical research" [ant: discouraging]
    2: furnishing support and encouragement; "the anxious child
       needs supporting and accepting treatment from the teacher"
       [syn: encouraging, supporting]

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "encouraging":
   alluring, animating, assuring, auspicious, bright with promise,
   challenging, cheerful, cheering, cheery, comforting, condolatory,
   condolent, condoling, consolatory, consoling, couleur de rose,
   energizing, enlivening, exciting, exhilarating, favorable,
   full of promise, galvanic, galvanizing, glad, gladdening,
   heart-warming, heartening, hospitable, inspiring, inspiriting,
   invigorating, inviting, joyful, likely, looking up,
   of good comfort, of promise, piquant, pregnant of good, promising,
   prompting, propitious, provocative, provoking, reassuring,
   relieving, rose-colored, roseate, rosy, rousing, stimulant,
   stimulating, stimulative, stirring, supportive, sympathetic