bush league vs minors

bush league and minors both are nouns.

Word	Noun	Adjective	Verb	Adverb
bush league	Yes	No	No	No
minors	Yes	No	No	No

As nouns, bush league and minors are synonyms defined as:

bush league and minors: a league of teams that do not belong to a major league (especially baseball)

Other synonyms of bush league include minor league.

bush league (noun)	minors (noun)
a league of teams that do not belong to a major league (especially baseball)	a league of teams that do not belong to a major league (especially baseball)