antagonist

Definition of Antagonist in English :

someone who offers opposition

2. antagonist

a muscle that relaxes while another contracts

Example Sentences:
'when bending the elbow the triceps are the antagonist'

3. antagonist

a drug that neutralizes or counteracts the effects of another drug

WordNet Lexical Database for English. Princeton University. 2010.

Antagonist

noun

1.

an opponent or adversary, as in a contest, drama, sporting event, etc

2.

any muscle that opposes the action of another

Compare agonist (sense 1)

3.

a drug that counteracts the effects of another drug

Compare synergist (sense 1)

noun

1.

a person who opposes or competes with another; adversary; opponent

2.

a muscle, drug, etc. that acts in opposition to or counteracts another

n.

1. One who opposes and contends against another; an adversary.

2. The principal character in opposition to the protagonist or hero of a narrative or drama.

3. Physiology A muscle that counteracts the action of another muscle, the agonist.

4. A drug or chemical substance that interferes with the physiological action of another, especially by combining with and blocking its receptor.