You searched for: “opponent muscle”
opponent muscle (s) (noun), opponent muscles (pl)
In anatomy, any of several muscles enabling the thumb to be moved toward a finger of the same hand: After slipping and falling on the icy sidewalk, Gary could not use his opponent muscles to move the thumb on his right hand.
This entry is located in the following unit: pon-, posit-, pos-, -poning, -poned, -ponency, -ponent, -ponement, -pound (page 6)