We have success with colour (5)
I believe the answer is:
white
'colour' is the definition.
(I know that white is a type of achromatic color)
'we have success' is the wordplay.
'have' means one lot of letters goes inside another.
'success' becomes 'hit' (a hit is a commercial success).
'we' placed around 'hit' is 'WHITE'.
'with' is the link.
(Other definitions for white that I've seen before include "See 10" , "The colour of snow" , "murderer" , "Colour of milk" , "See 9" .)