| noun | a person of subnormal intelligence |
| verb | cause to move more slowly or operate at a slower rate “This drug will retard your heart rate” |
| verb | be delayed |
| verb | slow the growth or development of “The brain damage will retard the child's language development” |
| verb | lose velocity; move more slowly “The car decelerated” |
| idiotic | adjective | having a mental age of three to seven years |
| imbecilic | adjective | having a mental age of three to seven years |
| cretinous | adjective | afflicted with cretinism |
| moronic | adjective | having a mental age of between eight and twelve years |
| retard | verb | slow the growth or development of |
| retardation | noun | any agent that retards or delays or hinders |
| retard | noun | a person of subnormal intelligence |
| delay | noun | time during which some action is awaited |
| deceleration | noun | a decrease in rate of change |
| slowing | noun | a decrease in rate of change |
| slowdown | noun | the act of slowing down or falling behind |