nab vs cop

nab is not a noun while cop is a noun.

Word	Noun	Adjective	Verb	Adverb
nab	No	No	Yes	No
cop	Yes	No	Yes	No

As verbs, nab and cop are synonyms defined as:

Other synonyms of nab include apprehend, arrest, collar, nail, pick up.

nab (noun)	cop (noun)
	uncomplimentary terms for a policeman

nab (verb)	cop (verb)
take into custody	take into custody
seize suddenly	take by theft
tag the base runner to get him out