Noun

• S: (n) idiot, imbecile, cretin, moron, changeling, half-wit, retard (a person of subnormal intelligence)

Verb

• S: (v) retard (cause to move more slowly or operate at a slower rate) "This drug will retard your heart rate"
• S: (v) retard (be delayed)
• S: (v) check, retard, delay (slow the growth or development of) "The brain damage will retard the child's language development"
• S: (v) decelerate, slow, slow down, slow up, retard (lose velocity; move more slowly) "The car decelerated"