Colour of bad part of egg (3-5)
I believe the answer is:
off-white
'colour' is the definition.
(off-white is a kind of colour)
'bad part of egg' is the wordplay.
'bad' becomes 'off' (I've seen this before).
'part of egg' becomes 'white'.
'off'+'white'='OFF-WHITE'
'of' is the link.
(Other definitions for off-white that I've seen before include "Very pale tint" , "something like cream" , "Very slightly yellowish or grey" , "Creamy?" , "Colour such as cream or bone" .)