I. ə-ˈpō-nənt noun
Etymology: Latin opponent-, opponens, present participle of opponere
Date: 1560
1. : one that takes an opposite position (as in a debate, contest, or conflict)
2. : a muscle that opposes or counteracts and limits the action of another
II. adjective
Date: 1647
1. : antagonistic , opposing
2. : situated in front