This is coloured, but not evenly (4)
I believe the answer is:
clue
'this' is the definition.
(the clue referring to itself!)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for clue that I've seen before include "Crossword hint?" , "Slight indication (as here)" , "Crossword aid" , "Aid to puzzlers" , "What's this" .)