1. Someone involved in a contest or battle (as in an agon)
   "The two agonists faced each other in the final round of the debate competition"
    
2. (biochemistry) a drug that can combine with a receptor on a cell to produce a physiological reaction
   "The new agonist showed promise in treating Parkinson's disease symptoms"
    
3. A muscle that contracts while another relaxes
   "when bending the elbow the biceps are the agonist"
    
4. [rare] The principal character in a work of fiction
   - protagonist

Derived forms: agonists

Type of: antagonistic muscle, character, contestant, drug, fictional character, fictitious character

Antonym: antagonist

Encyclopedia: Agonist