blue-gray vs blue-grey

blue-gray and blue-grey both are adjectives.

Word	Noun	Adjective	Verb	Adverb
blue-gray	No	Yes	No	No
blue-grey	No	Yes	No	No

As adjectives, blue-gray and blue-grey are synonyms defined as:

Other synonyms of blue-gray include bluish-gray, bluish-grey.

blue-gray (adjective)	blue-grey (adjective)
of grey tinged with blue	of grey tinged with blue