The Collaborative International Dictionary of English v.0.48:

Monophysite \Mo*noph"y*site\, n. [Gr. ?; mo`nos single + ?
   nature: cf. F. monophysite.] (Eccl. Hist.)
   One of a sect, in the ancient church, who maintained that the
   human and divine in Jesus Christ constituted but one
   composite nature. Also used adjectively.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Monophysite
    adj 1: of or relating to Monophysitism [syn: Monophysite,
           Monophysitic]
    n 1: an adherent of Monophysitism