counterpoise

counterpoise \KOUN-ter-poiz\, verb:

1. to balance by an opposing weight; counteract by an opposing force.
2. to bring into equilibrium.
3. Archaic. to weigh (one thing) against something else; consider carefully.

noun:
1. a counterbalancing weight.
2. any equal and opposing power or force.
3. the state of being in equilibrium; balance.
4. Radio. a network of wires or other conductors connected to the base of an antenna, used as a substitute for the ground connection.

To be unfortunate in any respect was sufficient, if there was no demerit to counterpoise it, to turn the scale of that good man's pity, and to engage his friendship and his benefaction.
-- Henry Fielding, Tom Jones, 1749

I know what she means all right. But I know something she doesn't know. Money is a good counterpoise to beauty.
-- Walker Percy, The Moviegoer, 1961

Counterpoise is from the Old French word countrepois which meant "to weigh against."