#1 agonist n. [protagonist] the principal character in a work of fiction. wn
#2 agonist n. someone involved in a contest or battle (as in an agon). wn
#3 agonist n. a muscle that contracts while another relaxes; "when bending the elbow the biceps are the agonist". wn
#4 agonist n. (biochemistry) a drug that can combine with a receptor on a cell to produce a physiological reaction. wn
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