reddish-grey vs reddish-gray

reddish-grey and reddish-gray both are adjectives.

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

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

Other synonyms of reddish-grey include red-gray, red-grey.

reddish-grey (adjective)	reddish-gray (adjective)
of grey tinged with red	of grey tinged with red