definition of
retardation

[1] #1 retardation n. [deceleration, slowing] a decrease in rate of change; "the deceleration of the arms race". wn

[2] #2 retardation n. the extent to which something is delayed or held back. wn

[3] #3 retardation n. [retardant, retardent] any agent that retards or delays or hinders; "flame-retardant". wn

[4] #4 retardation n. [mental retardation, backwardness, slowness, subnormality] lack of normal development of intellectual capacities. wn

[5] #5 retardation n. [slowdown, lag] the act of slowing down or falling behind. wn