grey-blue vs grayish-blue

grey-blue and grayish-blue both are adjectives.

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

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

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

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