Dictionary
coun•ter•vail
Pronunciation: (koun"tur-vāl'), [key]—
v.t.
1. to act or avail against with equal power, force, or effect; counteract.
2. to furnish an equivalent of or a compensation for; offset.
3. Archaic.to equal.
—
v.i.
to be of equal force in opposition; avail.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.