speed cop vs police officer

speed cop and police officer both are nouns.

Word	Noun	Adjective	Verb	Adverb
speed cop	Yes	No	No	No
police officer	Yes	No	No	No

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

speed cop: a policeman who rides a motorcycle (and who checks the speeds of motorists)
police officer: a member of a police force

Other hypernyms of speed cop include officer.

speed cop (noun)	police officer (noun)
a policeman who rides a motorcycle (and who checks the speeds of motorists)	a member of a police force