hold the line vs wait

hold the line is not a noun while wait is a noun.

Word	Noun	Adjective	Verb	Adverb
hold the line	No	No	Yes	No
wait	Yes	No	Yes	No

As verbs, wait is a hypernym of hold the line; that is, wait is a word with a broader meaning than hold the line:

Other hypernyms of hold the line include await, expect, look.

hold the line (noun)	wait (noun)
	the act of waiting (remaining inactive in one place while expecting something)
	time during which some action is awaited

hold the line (verb)	wait (verb)
hold the phone line open	look forward to the probable occurrence of
hold the line on prices; keep the price of something constant	serve as a waiter or waitress in a restaurant
	stay in one place and anticipate or expect something
	wait before acting