Greyish-yellow (4)
I believe the answer is:
ecru
'greyish-yellow' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ecru that I've seen before include "off-white" , "Find a cure, strangely, in the colour" , "Stange cure for a colour" , "Buff or beige" , "Light fawn colour" .)