adj (Colours) of a dark grey colourn (Colours) a dark grey colourThesaurus
Adj.
1.
slate-grey - of the color of slate or granite; "the slaty sky of dawn"slate-gray, slatey, slaty, slaty-gray, slaty-grey, stone-gray, stone-greyachromatic, neutral - having no hue; "neutral colors like black or white"