Source : Webster's Revised Unabridged Dictionary (1913)

Unipersonal \U"ni*per"son*al\, a. [Uni- + personal.]
   1. Existing as one, and only one, person; as, a unipersonal
      God.

   2. (Gram.) Used in only one person, especially only in the
      third person, as some verbs; impersonal.