Source : Webster's Revised Unabridged Dictionary (1913)

Exhortative \Ex*hor"ta*tive\, a. [L. exhortativus: cf. F.
   exhortatif.]
   Serving to exhort; exhortatory; hortative. --Barrow.

Source : WordNet®

exhortative
     adj : giving strong encouragement [syn: {exhortatory}, {hortative},
            {hortatory}]