peace officer vs law officer

peace officer and law officer both are nouns.

Word	Noun	Adjective	Verb	Adverb
peace officer	Yes	No	No	No
law officer	Yes	No	No	No

As nouns, peace officer and law officer are synonyms defined as:

Other synonyms of peace officer include lawman.

peace officer (noun)	law officer (noun)
an officer of the law	an officer of the law