agonist

(noun)

noun

1. the principal character in a work of fiction

Similar word(s): protagonist

Definition categories: person, character

2. someone involved in a contest or battle (as in an agon)

Definition categories: person, contestant

3. a muscle that contracts while another relaxes

- when bending the elbow the biceps are the agonist

Definition categories: body

4. (biochemistry) a drug that can combine with a receptor on a cell to produce a physiological reaction

Definition categories: man–made, drug

Sentences with agonist as a noun:

- "when bending the elbow the biceps are the agonist"

- "acetylcholine is an agonist at the a cholinergic receptor"