Greyish-yellow colour (4)
I believe the answer is:
ecru
'greyish-yellow colour' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ecru that I've seen before include "Unbleached-linen colour" , "Neutral colour" , "not whiter than white" , "Buff colour" , "Buff or beige" .)