A mousy grey (4)

I believe the answer is:

ashy

I believe this is a double definition.

'a mousy' is the first definition.
(thesaurus)

'grey' is the second definition.
(similar in meaning)

(Other definitions for ashy that I've seen before include "Wan" , "Like, eg, volcanic dust" , "Like burnt wood or coal" , "Deathly pale" , "pale greyish colour" .)

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app