hold over vs delay

hold over is not a noun while delay is a noun.

Word	Noun	Adjective	Verb	Adverb
hold over	No	No	Yes	No
delay	Yes	No	Yes	No

As verbs, delay is a hypernym of hold over; that is, delay is a word with a broader meaning than hold over:

hold over (noun)	delay (noun)
	the act of delaying; inactivity resulting in something being put off until a later time
	time during which some action is awaited

hold over (verb)	delay (verb)
intimidate somebody (with a threat)	cause to be slowed down or delayed
hold over goods to be sold for the next season	stop or halt
keep in a position or state from an earlier period of time	slow the growth or development of
continue a term of office past the normal period of time	act later than planned, scheduled, or required
hold back to a later time