ag·o·nist /ˈægənəst/ 名詞
Ag·o·nist n. One who contends for the prize in public games. [R.]
n 1: the principal character in a work of fiction [syn: protagonist]
2: someone involved in a contest or battle (as in an agon)
3: a muscle that contracts while another relaxes; "when bending
the elbow the biceps are the agonist"
4: (biochemistry) a drug that can combine with a receptor on a
cell to produce a physiological reaction