noun
: a gambling game derived from the earlier thimblerig and in which a person by sleight-of-hand manipulates a pea or similar pellet and three half walnut shells or similar cuplike objects so that a spectator can seldom know surely under which shell the pea rests and then invites bets on the location of the pea
the shell game is so often played dishonestly that its name has become symbolic of chicanery
— compare three-card monte