outing vs field day

outing and field day both are nouns.

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

As nouns, outing and field day are synonyms defined as:

Other synonyms of outing include picnic.

outing (noun)	field day (noun)
a journey taken for pleasure	a day for outdoor athletic competition
a day devoted to an outdoor social gathering	a day devoted to an outdoor social gathering
	(military) a day for military exercises and display
	a time of unusual pleasure and success