From WordNet (r) 2.0 (August 2003) [wn]:
grayish
adj : an achromatic color of any lightness between the extremes of
black and white; "gray flannel suit"; "hair just
turning gray" [syn: gray, grey, greyish]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Grayish \Gray"ish\, a.
Somewhat gray.
[1913 Webster]