monothelitism

from The Century Dictionary.

• noun The doctrine that in the person of Christ there are but one will and one energy or operation; opposed to the orthodox doctrine (dyothelism) that since the incarnation Christ has two distinct wills, the divine and the human, and two distinct but harmonious operations.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the theological doctrine that Christ had only one will even though he had two natures (human and divine); condemned as heretical in the Third Council of Constantinople