All 4 Uses

forfeit
in
The Westing Game
(Edited)

Forfeits: If any player drops out, the partner must leave the game.
p. 32.3

forfeits = penalties
Absent pairs forfeit the $10,000; their clues will be held until the next session.
p. 32.4

forfeit = lose
The forfeited money upset her more than the murder of her uncle, if he was her uncle.
p. 40.3 *

forfeited = lost (given up)
I, Samuel W. Westing, otherwise known as Sandy McSouthers and others, do hereby give and bequeath all the property and possessions in my name as follows: To all of you, in equal shares, the deed to Sunset Towers; And to my former wife, Berthe Erica Crow, the ten-thousand-dollar check forfeited by table one, and two ten-thousand-dollar checks endorsed by J.J. Ford and Alexander McSouthers.
p. 171.3

forfeited = given up or lost

Definitions:

(1) (forfeit)
to lose or surrender something -- often as a penalty
(2) (meaning too rare to warrant focus)
More rarely, forfeit is used as a noun to reference that which was lost or surrendered.