Source : Webster's Revised Unabridged Dictionary (1913)

Consensual \Con*sen"su*al\, a. [See {Consent}, v. i., and cf.
   {Sensual}.]
   1. (Law) Existing, or made, by the mutual consent of two or
      more parties.

   2. (Physiol.) Excited or caused by sensation, sympathy, or
      reflex action, and not by conscious volition; as,
      consensual motions.

   {Consensual contract} (Law), a contract formed merely by
      consent, as a marriage contract.

Source : WordNet®

consensual
     adj : existing by consent; "a consensual contract"