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.

Definitions of retard
  1. verb
    cause to move more slowly or operate at a slower rate
    “This drug will retard your heart rate”
    see moresee less
    lessen the momentum or velocity of
    type of:
    decelerate, slow down
    reduce the speed of
  2. verb
    lose velocity; move more slowly
    synonyms: decelerate, slow, slow down, slow up
    see moresee less
    accelerate, quicken, speed, speed up
    move faster
    show 8 types...
    hide 8 types...
    slow, slow down, slow up
    cause to proceed more slowly
    delay, detain, hold up
    cause to be slowed down or delayed
    bog, bog down
    cause to slow down or get stuck
    clog, constipate
    impede with a clog or as if with a clog
    engage in delaying tactics or refuse to cooperate
    delay or hold up; prevent from proceeding on schedule or as planned
    deliberately delay an event or action
    buy time
    act so as to delay an event or action in order to gain an advantage
    type of:
    decrease, diminish, fall, lessen
    decrease in size, extent, or range
  3. verb
    slow the growth or development of
    “The brain damage will retard the child's language development”
    synonyms: check, delay
    see moresee less
    check; keep in check (a fire)
    delay, detain, stay
    stop or halt
    type of:
    alter, change, modify
    cause to change; make different; cause a transformation
  4. verb
    be delayed
    see moresee less
    type of:
    have the quality of being; (copula, used with an adjective or a predicate noun)
  5. noun
    a person of subnormal intelligence
    synonyms: changeling, cretin, half-wit, idiot, imbecile, moron
    see moresee less
    type of:
    simple, simpleton
    a person lacking intelligence or common sense
Word Family

Test prep from the experts

Boost your test score with programs developed by’s experts.

  • Proven methods: Learn faster, remember longer with our scientific approach.
  • Personalized plan: We customize your experience to maximize your learning.
  • Strategic studying: Focus on the words that are most crucial for success.


  • Number of words: 500+
  • Duration: 8 weeks or less
  • Time: 1 hour / week


  • Number of words: 500+
  • Duration: 10 weeks or less
  • Time: 1 hour / week


  • Number of words: 700+
  • Duration: 10 weeks
  • Time: 1 hour / week