White people vs Caucasian race

White people and Caucasian race both are nouns.

Word	Noun	Adjective	Verb	Adverb
White people	Yes	No	No	No
Caucasian race	Yes	No	No	No

As nouns, White people and Caucasian race are synonyms defined as:

Other synonyms of White people include Caucasoid race, White race.

White people (noun)	Caucasian race (noun)
a light-skinned race	a light-skinned race