holiday vs vac

holiday and vac both are nouns.

Word	Noun	Adjective	Verb	Adverb
holiday	Yes	No	Yes	No
vac	Yes	No	No	No

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

Other hyponyms of holiday include half-term, vacay, field day, outing, picnic, honeymoon, paid vacation, winter break.

holiday (noun)	vac (noun)
leisure time away from work devoted to rest or pleasure	informal term for vacation
a day on which work is suspended by law or custom

holiday (verb)	vac (verb)
spend or take a vacation