Someone involved in a contest or battle (as in an agon), protagonist. / The muscle that contracts while the other relaxes.

The range of activities associated with aggressive encounters between members of the same species, including threat, attack, appeasement, or retreat.

Of or relating to contests that were originally participated in by the Ancient Greeks; athletic. / (zoology, anthropology) Characterised by conflict or hostility. / (rhetoric) Argumentative; combative.

(archaic) agonistic (of or relating to contests that were originally participated in by the Ancient Greeks).

A person engaged in a struggle.

plural of agonist

By means of, or in terms of, agonists.

(biochemistry) A drug or other chemical that can combine with a receptor on a cell to produce a physiologic reaction typical of a naturally occurring substance. Co-agonist implies it is one of other agonists working in conjunction.

plural of co-agonist

(immunology) A monoclonal antibody that aims to boost the human immune system either to fight infection or cancer.