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retard

American  
[ri-tahrd, ree-tahrd] / rɪˈtɑrd, ˈri tɑrd /

verb (used with object)

retards, present (3rd person singular) retarded, past participle, past retarding present participle
  1. to make slow; delay the development or progress of (an action, process, etc.); hinder or impede.

    Synonyms:
    check, obstruct
    Antonyms:
    accelerate

verb (used without object)

retards, present (3rd person singular) retarded, past participle, past retarding present participle
  1. to be delayed.

noun

retards plural
  1. a slowing down, diminution, or hindrance, as in a machine.

  2. Slang: Disparaging and Offensive.

    1. a contemptuous term used to refer to a person who is cognitively impaired.

    2. a person who is stupid, obtuse, or ineffective in some way.

  3. Automotive, Machinery. an adjustment made in the setting of the distributor of an internal-combustion engine so that the spark for ignition in each cylinder is generated later in the cycle.

retard British  

verb

  1. (tr) to delay or slow down (the progress, speed, or development) of (something)

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

noun

  1. offensive a retarded person

  2. offensive a foolish person

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Sensitive Note

See retarded.

Other Word Forms

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Inflected Forms

Nouns

Participles

Conjugated Forms

Present

Past

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Etymology

Origin of retard

First recorded in 1480–90; from Latin retardāre to delay, protract, equivalent to re- re- + tardāre “to loiter, be slow,” derivative of tardus “slow”; see tardy

Explanation

To retard something is to slow it down. A lack of fresh fruit and vegetables can retard the growth of a young child. This word should be used with a lot of caution. Using this word to describe a person is considered offensive and should be avoided. It is often a harmless word when used as a verb. While skiing, a heavy, bulky jacket could retard your progress down the mountain. Keeping a plant out of sunlight would retard its growth.

Keep Reading on Vocabulary.com

Vocabulary lists containing retard

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

A case in point is a bill on New York Gov. Kathy Hochul’s desk that would retard artificial intelligence in the name of protecting public safety.

From The Wall Street Journal Dec. 11, 2025

The giant trees resist burning thanks to the bark, up to about 30 centimeters thick at the base, which contains tannic acids that retard flames.

From Science Magazine Dec. 1, 2023

"Going forward, we'll be able to do tests on mice to see if new molecules that stabilise mitochondrial and autophagic function can retard the disease."

From Science Daily Nov. 1, 2023

“Although you may retard an ignition or a fire spread for this season, what you’ve done is grown a lot more biomass to burn in the next year,” he said.

From Los Angeles Times Jul. 3, 2023

I resolved, therefore, that if my immediate union with my cousin would conduce either to hers or my father’s happiness, my adversary’s designs against my life should not retard it a single hour.

From "Frankenstein" by Mary Shelley

If the levels of solutes increase beyond a certain range, a hormone is released that retards water loss through the kidney and dilutes the blood to safer levels.

From Textbooks Jun. 9, 2022

Prior Vital Dufour, who was ordained Cardinal of the Catholic church by Pope Clement in 1313, once listed 40 of the virtues of Armagnac including: "It renders man joyous, preserves youth and retards senility."

From BBC May 28, 2022

Earlier, Holder posted a tweet that simply stated the law regarding the fines and imprisonment of up to six months that anyone who “willfully obstructs or retards the passage of the mail” can face.

From Slate Aug. 15, 2020

We found out it preserves the cells and retards the damage.

From New York Times Sep. 22, 2012

Since a high temperature retards assimilation, promotes deleterious tissue-change, and causes rapid emaciation and loss of strength, measures designed to reduce it are urgently needed.

From A System of Practical Medicine by American Authors, Vol. I Volume 1: Pathology and General Diseases by Various

Based on some of the results, the team thinks microbes retarded the growth of inbreds, rather than giving the hybrids a special boost.

From Science Magazine Jul. 29, 2021

Supreme Court ruled that states may not execute “mentally retarded offenders.”

From Slate May 22, 2020

In 2002, Justice Stevens wrote the majority opinion in a 6 to 3 decision that banned the death penalty for the mentally retarded.

From Seattle Times Jul. 16, 2019

But millennials’ progress through life has been measurably retarded by the Great Recession, a two-track labor market in which many high-paying jobs require a college education and record levels of student debt.

From Washington Post Mar. 16, 2019

Even exposures to less than lethal quantities may in the end cause death of the larvae, for inevitably the growth rate is retarded.

From "Silent Spring" by Rachel Carson

Their opposition to transportation projects and other infrastructure, though supposedly grounded in Jeffersonian principle, was a roundabout way of retarding industrial development and ensuring that slavery did not become an economic anachronism.

From Salon Jul. 26, 2025

That drove prices in Europe and Asia to all-time highs earlier this year, fanning inflationary pressure and retarding efforts by countries to switch to gas from coal to reduce pollution and carbon emissions.

From Reuters May 27, 2022

If an object is slid along a rough horizontal floor, it soon comes to rest because friction between it and the floor acts as a retarding force.

From Textbooks Oct. 13, 2016

It was Rivera, of course, who attracted the most attention, retarding the acknowledgement due to Siqueiros and Orozco.

From The Guardian Jun. 29, 2013

I had begun to believe that the Mediterranean Diet that kept my grandmother alive against her will was also sinisterly retarding my maturity.

From "Middlesex: A Novel" by Jeffrey Eugenides

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