retarded

UK: /rɪˈtɑː^rdɪd/ US: /rɪˈtɑrdɪd/ ,(ri tär′did)

WordReference Random House Learner's Dictionary of American English © 2025

re•tard•ed /rɪˈtɑrdɪd/   adj. 

1. Psychiatry less developed mentally than others;
   lacking normal intelligence:
   a retarded child.

n. 

2. Psychiatry the retarded, [plural* used with a plural verb] mentally retarded people thought of as a group:
   fought for rights for the retarded.

WordReference Random House Unabridged Dictionary of American English © 2025

re•tard•ed  (ri tär′did), adj. 

1. Psychiatry characterized by retardation:
   a retarded child.

n. 

2. Psychiatry (used with a pl. v.) mentally retarded persons collectively (usually prec. by the):
   new schools for the retarded.

• retard + -ed² 1800–10

Synonyms

backward, disabled, handicapped.

Collins Concise English Dictionary © HarperCollins Publishers::

retarded / rɪˈtɑːdɪd/ adjective

1. having learning difficulties

WordReference Random House Learner's Dictionary of American English © 2025

re•tard /rɪˈtɑrd for 1.; ˈritɑrd for 4 in Unabridged dictionary.    v. [~ + object]

1. to delay the development or progress of:
   Cold retards the growth of bacteria.

n. [countable]

2. Slang Terms (disparaging).
   • a mentally retarded person.
   • one who is stupid or ineffective.

re•tar•da•tion /ˌritɑrˈdeɪʃən/  n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2025

re•tard  (ri tärd′, for 1–3, 5; rē′tärd for 4), v.t. 

1. to make slow;
   delay the development or progress of (an action, process, etc.);
   hinder or impede.

v.i. 

2. to be delayed.

n. 

3. a slowing down, diminution, or hindrance, as in a machine.
4. Slang Terms (disparaging).
   • a mentally retarded person.
   • a person who is stupid, obtuse, or ineffective in some way:
     a hopeless social retard.
5. Automotive 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. Cf. advance. 

• Latin retardāre to delay, protract, equivalent. to re- re- + tardāre to loiter, be slow, derivative of tardus slow; see tardy
• 1480–90

re•tard′ing•ly, adv. 
Synonyms

• 1. obstruct, check.

Antonyms

• 1. accelerate.

Collins Concise English Dictionary © HarperCollins Publishers::

retard verb / rɪˈtɑːd/

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

noun / ˈriːtɑːd/

1. a person with learning difficulties
2. a foolish person

Etymology: 15th Century: from Old French retarder, from Latin retardāre, from re- + tardāre to make slow, from tardus sluggish; see tardy