beef vs bully beef

beef and bully beef both are nouns.

Word	Noun	Adjective	Verb	Adverb
beef	Yes	No	Yes	No
bully beef	Yes	No	No	No

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

Other hyponyms of beef include ground beef, hamburger, corn beef, corned beef, pastrami.

beef (noun)	bully beef (noun)
cattle that are reared for their meat	beef cured or pickled in brine
informal terms for objecting
meat from an adult domestic bovine

beef (verb)	bully beef (verb)
complain