Source : Webster's Revised Unabridged Dictionary (1913)

Deism \De"ism\ (d[=e]"[i^]z'm), n. [L. deus god: cf. F.
   d['e]isme. See {Deity}.]
   The doctrine or creed of a deist; the belief or system of
   those who acknowledge the existence of one God, but deny
   revelation.

   Note: Deism is the belief in natural religion only, or those
         truths, in doctrine and practice, which man is to
         discover by the light of reason, independent of any
         revelation from God. Hence, deism implies infidelity,
         or a disbelief in the divine origin of the Scriptures.

Source : WordNet®

deism
     n : the form of theological rationalism that believes in God on
         the basis of reason without reference to revelation [syn:
          {free thought}]