workwear vs blue jeans

workwear and blue jeans both are nouns.

Word	Noun	Adjective	Verb	Adverb
workwear	Yes	No	No	No
blue jeans	Yes	No	No	No

As nouns, blue jeans is a hyponym of workwear; that is, blue jeans is a word with a more specific, narrower meaning than workwear:

workwear: heavy-duty clothes for manual or physical work
blue jeans: (used in the plural) close-fitting trousers of heavy denim for manual work or casual wear

Other hyponyms of workwear include denim, jeans, work-shirt.

workwear (noun)	blue jeans (noun)
heavy-duty clothes for manual or physical work	(used in the plural) close-fitting trousers of heavy denim for manual work or casual wear