retardation

American  

[ree-tahr-dey-shuhn] / ˌri tɑrˈdeɪ ʃən /

Also retardment

noun

1. the act of retarding or state of being retarded.

2. something that retards; hindrance.

3. Usually Offensive. slowness or limitation in intellectual understanding and awareness, emotional development, academic progress, etc.

4. Music. a form of suspension that is resolved upward.

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retardation British  

/ ˌriːtɑːˈdeɪʃən, rɪˈtɑːdmənt /

noun

1. the act of retarding or the state of being retarded

2. something that retards; hindrance

3. the rate of deceleration

4. psychiatry the slowing down of mental functioning and bodily movement

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Sensitive Note

See retarded.

Other Word Forms

• nonretardation
  noun
• nonretardative
  adjective
• nonretardatory
  adjective
• nonretardment
  noun
• retardative
  adjective
• retardatory
  adjective

Etymology

Origin of retardation

First recorded in 1400–50; late Middle English retardacioun, from Latin retardātiōn- (stem of retardātiō ), equivalent to retardāt(us) ( see retard, -ate ¹) + -iōn- noun suffix ( see -ion)

Explanation

Retardation is often used to describe problems in human mental development that result in a lack of intelligence or other kinds of physical or learning delays. Retardation can also indicate when something is kept from growing or developing fully. A lack of sunlight might cause retardation of your tomato plants, for example, stunting their growth. You can use retardation to describe other kinds of slowness or delays too, including simply a decrease in speed. In fact, the Latin root word, retardare, means "to make slow, delay, keep back, or hinder."

Example Sentences

Clinicians might also be less frequently assigning other labels such as intellectual disability, formally referred to as mental retardation, some data suggest.

From The Wall Street Journal • Oct. 14, 2025

It accused Bang and Owoc of touting their energy drink with "Super Creatine" as a "miracle drink" that can "reverse mental retardation" and help cure neurological disorders.

From Reuters • Apr. 12, 2023

Risks to the fetuses in high-order pregnancies include "intrauterine growth retardation, respiratory distress syndrome, miscarriage, and preterm delivery."

From Salon • Jul. 4, 2022

The term mental retardation was often a medical diagnosis for people with intellectual or developmental disabilities.

From Seattle Times • Mar. 26, 2021

I told her that doctors used to use the word idiocy to refer to mental retardation, and to the brain damage that accompanied hereditary syphilis.

From "The Immortal Life of Henrietta Lacks" by Rebecca Skloot