holiday vs field day

holiday and field day both are nouns.

Word	Noun	Adjective	Verb	Adverb
holiday	Yes	No	Yes	No
field day	Yes	No	No	No

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

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

holiday (noun)	field day (noun)
leisure time away from work devoted to rest or pleasure	a day for outdoor athletic competition
a day on which work is suspended by law or custom	a day devoted to an outdoor social gathering
	(military) a day for military exercises and display
	a time of unusual pleasure and success

holiday (verb)	field day (verb)
spend or take a vacation