dummy

Concise Oxford English Dictionary © 2008 Oxford University Press:
dummy/ˈdʌmi/

▶noun (pl. dummies)

• 1 a model or replica of a human being.

• 2 an object designed to resemble and serve as a substitute for the real one.

  ■ Brit. a rubber or plastic teat for a baby to suck on.

• 3 (chiefly in rugby and soccer) a feigned pass or kick.

• 4 Bridge the declarer's partner, whose cards are exposed on the table after the opening lead and played by the declarer.

  ■ (in whist) an imaginary fourth player.

• 5 informal, chiefly N. Amer. a stupid person.

▶verb (dummies, dummying, dummied)

• 1 (chiefly in rugby and soccer) feign a pass or kick.

• 2 (dummy up) N. Amer. informal keep quiet.

– phrases
sell someone a dummy (chiefly in rugby and soccer) deceive an opponent by feigning a pass or kick.

– origin C16 (orig. ‘a person who cannot speak’, later ‘an imaginary fourth player in whist’): from dumb + -y1.