See deforce in American Heritage Dictionary 4
transitive verb de·forced, de·forc·ing, de·forc·es
Origin:
Origin: Middle English deforcen
Origin: , from Anglo-Norman deforcer
Origin: , from Old French desforcier
Origin: : des-, de-
Origin: + forcier, to force (from Vulgar Latin *fortiāre, from Latin fortis, strong; see bhergh-2 in Indo-European roots)
.Related Forms: