retardation vs holdup

retardation and holdup both are nouns.

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

As nouns, holdup is a hypernym of retardation; that is, holdup is a word with a broader meaning than retardation:

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

Other hypernyms of retardation include delay.

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