agonist
noun(ag-o-nist)
the principal character in a work of fiction
agonist
noun(ag-o-nist)
a muscle that contracts while another relaxes
Examples:
When bending the elbow the biceps are the agonist.
agonist
noun(ag-o-nist)
(biochemistry) a drug that can combine with a receptor on a cell to produce a physiological reaction
agonist
noun(ag-o-nist)
someone involved in a contest or battle (as in an agon)