retardation

noun

1.
a decrease in rate of change
deceleration slowing
Derived from:
retard
2.
the extent to which something is delayed or held back
Derived from:
retard
3.
any agent that retards or delays or hinders
retardant retardent
Derived from:
retard
4.
lack of normal development of intellectual capacities
backwardness mental retardation slowness subnormality
Derived from:
retard
5.
the act of slowing down or falling behind
lag slowdown
Derived from:
retard