dummy

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun An imitation of a real or original object, intended to be used as a practical substitute.
• noun A mannequin used in displaying clothes.
• noun A figure of a person or an animal manipulated by a ventriloquist.
• noun A stuffed or pasteboard figure used as a target.
• noun Football A heavy stuffed cylindrical bag used for blocking and tackling practice.
• noun A stupid person; a dolt.
• noun A silent or taciturn person.
• noun Law A person or entity that is the named party to a transaction but that acts on behalf of another concealed person or entity.
• noun A person or an agency secretly in the service of another.
• noun One of a set of model pages with text and illustrations pasted into place to direct the printer.
• noun A set of bound blank pages used as a model to show the size and general appearance of a book being published.
• noun The partner in bridge who exposes his or her hand to be played by the declarer.
• noun The hand thus exposed.
• noun Computers A character or other piece of information entered into a computer only to meet prescribed conditions, such as word length, and having no effect on operations.
• adjective Simulating or replacing something but lacking its function.
• adjective Serving as a front or cover for another.
• adjective Games Played with a dummy.
• adjective Computers Entered or provided only to meet prescribed conditions.
• transitive verb To make a model of (a publication or page).

from The Century Dictionary.

• To act as a dummy. See dummy, 6.
• noun Proofs of pages of composed type pasted down upon a larger leaf in proper order, to show the general arrangement of an intended book or pamphlet.
• noun The dealer's partner at bridge.
• noun In the game of rounce, an extra hand of 6 cards in the center of the table.
• noun A person who is put forward (by interested parties in the background) in some capacity in connection with a matter in which he has no real concern or as to which he is the mere tool of his movers: for example, as an incorporater or a director of a bank, a railway, or other company, in order to satisfy some statutory requirement as to number, place of residence, or the like, or as in Australia, when the public lands were thrown open, one who made application for an allotment in his own name, but really on behalf of another who had already made his own ‘selection.’
• noun A horse affected with dumminess, which follows an acute inflammation of the brain. See dumminess, 2.
• noun One who is dumb; a dumb person; a mute.
• noun One who is silent; specifically, in theatrical, a person on the stage who appears before the lights, but has nothing to say.
• noun One who or that which lacks the reality, force, function, etc., which it appears to possess; something that imitates a reality in a mechanical way or for a mechanical purpose.
• noun In mech.:
• noun A dumb-waiter.
• noun A locomotive with a condensing-engine, and hence avoiding the noise of escaping steam: used especially for moving railroad-cars in the streets of a city, or combined in one with a passenger-car for local or street traffic.
• noun The name given by firemen to one of the jets from the mains or chief water-pipes.
• noun A hatters' pressing-iron.
• noun In card-playing:
• noun An exposed hand of cards, asin whist when three play.
• noun A game of whist in which three play, the fourth hand being placed face up. One player, with this and his own hand, plays against the other two.
• Silent; mute.
• Sham; fictitious; feigned: as, a dummy watch.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Silent; mute; noiseless; as a dummy engine.
• adjective Fictitious or sham; feigned.
• adjective See under Car.
• noun One who is dumb.
• noun A sham package in a shop, or one which does not contain what its exterior indicates.
• noun An imitation or copy of something, to be used as a substitute; a model; a lay figure; as, a figure on which clothing is exhibited in shop windows; a blank paper copy used to show the size of the future book, etc.
• noun (Drama) One who plays a merely nominal part in any action; a sham character.