holdup vs retardation

holdup and retardation both are nouns.

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

As nouns, retardation is a hyponym of holdup; that is, retardation is a word with a more specific, narrower meaning than holdup:

holdup: the act of delaying; inactivity resulting in something being put off until a later time
retardation: the act of slowing down or falling behind

holdup (noun)	retardation (noun)
robbery at gunpoint	the act of slowing down or falling behind
the act of delaying; inactivity resulting in something being put off until a later time	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