lawman vs officer

lawman and officer both are nouns.

Word	Noun	Adjective	Verb	Adverb
lawman	Yes	No	No	No
officer	Yes	No	Yes	No

As nouns, officer is a hyponym of lawman; that is, officer is a word with a more specific, narrower meaning than lawman:

lawman (noun)	officer (noun)
an officer of the law	a member of a police force
	someone who is appointed or elected to an office and who holds a position of trust
	any person in the armed services who holds a position of authority or command
	a person authorized to serve in a position of authority on a vessel

lawman (verb)	officer (verb)
	direct or command as an officer