retardation vs retard

retardation and retard both are nouns.

Word	Noun	Adjective	Verb	Adverb
retardation	Yes	No	No	No
retard	Yes	No	Yes	No

retardation (noun)	retard (noun)
the act of slowing down or falling behind	a person of subnormal intelligence
a decrease in rate of change
lack of normal development of intellectual capacities
any agent that retards or delays or hinders
the extent to which something is delayed or held back

retardation (verb)	retard (verb)
	lose velocity; move more slowly
	cause to move more slowly or operate at a slower rate
	slow the growth or development of
	be delayed