blue jeans vs workwear

blue jeans and workwear both are nouns.

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

As nouns, workwear is a hypernym of blue jeans; that is, workwear is a word with a broader meaning than blue jeans:

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

Other hypernyms of blue jeans include pair of trousers, pant, trousers.

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