A dummy is something used as a pretend person or thing.
When we talk about dummies, people often think it's only in the context of comedy or entertainment. You might hear someone say "I'm just going to be a dummy and not understand this joke" which means they're pretending to be clueless on purpose. But dummies can also refer to objects used for training or practice. For example, medical students use fake bodies called dolls or mannequins as dummies to learn how to do operations safely. Some people even talk about a dummy as a block of wood or other object used in carpentry to help them practice their measuring and cutting skills.
How common is "dummy"?
Word dummy is considered rare in modern English. It has a balanced usage among all categories: speech, fiction, newspapers and academic texts.
Definitions
noun
(dated) A silent person; a person who does not talk.
A stupid person.
Example: Don't be such a dummy!
(African-American Vernacular, Baltimore, slang) A term of address.
Example: Hey dummy, what's good wit chu?
A figure of a person or animal used by a ventriloquist; a puppet.
Something constructed with the size and form of a human, to be used in place of a person.
Example: To understand the effects of the accident, we dropped a dummy from the rooftop.
A person who is the mere tool of another; a man of straw.
A deliberately nonfunctional device or tool used in place of a functional one.
Example: The hammer and drill in the display are dummies.
(Australia, New Zealand, UK, Ireland) A pacifier; a plastic or rubber teat used to soothe or comfort a baby.
Example: The baby wants her dummy.
(card games, chiefly bridge) A player whose hand is shown and is to be played from by another player.
(linguistics) A word serving only to make a construction grammatical.
Example: The pronoun "it" in "It's a mystery why this happened" is a dummy.
(programming) An unused parameter or value.
Example: If flag1 is false, the other parameters are dummies.
(sports, chiefly rugby, soccer) A feigned pass or kick or play in order to deceive an opponent.
(sports, UK) A bodily gesture meant to fool an opposing player; a feint.
(attributive) A newborn animal that is indifferent to stimulus and does not voluntarily move.
Example: a dummy calf, lamb, or foal
(chess) A fairy chess piece that cannot move or capture, but can be captured and used to skip moving another piece.
