dummy

The definition of a dummy is a fool, or a figure made to look like a person.

(noun)

An example of a dummy is a person who makes the same silly mistake over and over again.
An example of a dummy is a figure used in seat belt testing.

Dummy means fake.

(adjective)

An example of dummy used as an adjective is in the phrase "dummy trap," which means a fake trap.

See dummy in Webster's New World College Dictionary

noun pl. dummies

Slang a person unable to talk; mute: an offensive term
a figure made in human form, as for displaying clothing, practicing tackling in football, etc.
an imitation or sham; substitute for the real thing, as an empty container or false drawer
a person secretly acting for another while apparently representing his or her own interests
Slang a stupid person
Bridge
1. the declarer's partner, whose hand is arranged face up on the table and played by the declarer
2. such a hand
Printing
1. a set of pages with the layout, as for a magazine
2. a bound volume with blank pages, used as a model for a planned book

Origin: < dumb + -y

adjective

intransitive verb dummied, dummying

Slang used only in the phrase, to refuse to talk or tell what one knows

See dummy in American Heritage Dictionary 4

noun pl. dum·mies

An imitation of a real or original object, intended to be used as a practical substitute.
a. A mannequin used in displaying clothes.
b. A figure of a person or an animal manipulated by a ventriloquist.
c. A stuffed or pasteboard figure used as a target.
d. Football A heavy stuffed cylindrical bag used for blocking and tackling practice.
A stupid person; a dolt.
A silent or taciturn person.
A person or an agency secretly in the service of another.
Printing
a. One of a set of model pages with text and illustrations pasted into place to direct the printer. Also called dummy page.
b. A set of bound blank pages used as a model to show the size and general appearance of a book being published.
Games
a. The partner in bridge who exposes his or her hand to be played by the declarer.
b. The hand thus exposed.
Computer Science 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: a dummy pocket.
Serving as a front or cover for another: a dummy corporation.
Games Played with a dummy.
Computer Science Entered or provided only to meet prescribed conditions: a dummy variable.