vox populi vs public opinion

vox populi and public opinion both are nouns.

Word	Noun	Adjective	Verb	Adverb
vox populi	Yes	No	No	No
public opinion	Yes	No	No	No

As nouns, vox populi and public opinion are synonyms defined as:

vox populi and public opinion: a belief or sentiment shared by most people; the voice of the people

Other synonyms of vox populi include opinion, popular opinion.

vox populi (noun)	public opinion (noun)
a belief or sentiment shared by most people; the voice of the people	a belief or sentiment shared by most people; the voice of the people