pig vs police officer

pig and police officer both are nouns.

Word	Noun	Adjective	Verb	Adverb
pig	Yes	No	Yes	No
police officer	Yes	No	No	No

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

Other hypernyms of pig include officer.

pig (noun)	police officer (noun)
domestic swine	a member of a police force
a crude block of metal (lead or iron) poured from a smelting furnace
mold consisting of a bed of sand in which pig iron is cast
a person regarded as greedy and pig-like
uncomplimentary terms for a policeman
a coarse obnoxious person