fashion business vs apparel industry

fashion business and apparel industry both are nouns.

Word	Noun	Adjective	Verb	Adverb
fashion business	Yes	No	No	No
apparel industry	Yes	No	No	No

As nouns, fashion business and apparel industry are synonyms defined as:

fashion business and apparel industry: makers and sellers of fashionable clothing

Other synonyms of fashion business include fashion industry, garment industry, rag trade.

fashion business (noun)	apparel industry (noun)
makers and sellers of fashionable clothing	makers and sellers of fashionable clothing