fete champetre vs lawn party

fete champetre and lawn party both are nouns.

Word	Noun	Adjective	Verb	Adverb
fete champetre	Yes	No	No	No
lawn party	Yes	No	No	No

As nouns, fete champetre and lawn party are synonyms defined as:

fete champetre and lawn party: a party of people assembled for social interaction out of doors

Other synonyms of fete champetre include garden party.

fete champetre (noun)	lawn party (noun)
a party of people assembled for social interaction out of doors	a party of people assembled for social interaction out of doors