Ranger vs law officer

Ranger and law officer both are nouns.

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

As nouns, law officer is a hypernym of Ranger; that is, law officer is a word with a broader meaning than Ranger:

Ranger: a member of the Texas state highway patrol; formerly a mounted lawman who maintained order on the frontier
law officer: an officer of the law

Other hypernyms of Ranger include lawman, peace officer.

Ranger (noun)	law officer (noun)
a member of the Texas state highway patrol; formerly a mounted lawman who maintained order on the frontier	an officer of the law