blue jeans vs jeans

blue jeans and jeans both are nouns.

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

As nouns, blue jeans and jeans are synonyms defined as:

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

Other synonyms of blue jeans include denim.

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