policewoman vs woman

policewoman and woman both are nouns.

Word	Noun	Adjective	Verb	Adverb
policewoman	Yes	No	No	No
woman	Yes	No	No	No

As nouns, woman is a hypernym of policewoman; that is, woman is a word with a broader meaning than policewoman:

Other hypernyms of policewoman include officer, police officer, adult female.

policewoman (noun)	woman (noun)
a woman policeman	women as a class
	an adult female person (as opposed to a man)
	a female person who plays a significant role (wife or mistress or girlfriend) in the life of a particular man