1. constrain, oblige, coerce. Compel, impel agree in the idea of using physical or other force to cause something to be done. Compel means to constrain someone, in some way, to yield or to do what one wishes: to compel a recalcitrant debtor to pay; Fate compels us to face danger and trouble. Impel may mean literally to push forward, but is usually applied figuratively, meaning to provide a strong motive or incentive toward a certain end: Wind impels a ship. Curiosity impels me to ask. 3. overpower, bend.