oxford-grey vs dark-grey

oxford-grey and dark-grey both are adjectives.

Word	Noun	Adjective	Verb	Adverb
oxford-grey	No	Yes	No	No
dark-grey	No	Yes	No	No

As adjectives, oxford-grey and dark-grey are synonyms defined as:

Other synonyms of oxford-grey include dark-gray, oxford-gray.

oxford-grey (adjective)	dark-grey (adjective)
of a dark shade of grey	of a dark shade of grey