holdup vs inactivity

holdup and inactivity both are nouns.

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

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

holdup: the act of delaying; inactivity resulting in something being put off until a later time
inactivity: being inactive; being less active

holdup (noun)	inactivity (noun)
robbery at gunpoint	being inactive; being less active
the act of delaying; inactivity resulting in something being put off until a later time	a disposition to remain inactive or inert
	the state of being inactive