Monophysite
noun
Mo·noph·y·site mə-ˈnä-fə-ˌsīt 
: one holding the doctrine that Christ has a single inseparable nature that is at once divine and human rather than having two distinct but unified natures
Monophysite adjective
or Monophysitic
mə-ˌnä-fə-ˈsi-tik
Monophysitism
mə-ˈnä-fə-ˌsī-ˌti-zəm
noun 
Word History
Etymology
Medieval Latin Monophysita, from Middle Greek Monophysitēs, from Greek mon- + physis nature — more at physics
First Known Use
1659, in the meaning defined above