Exclamation of Scot about colour (5)
I believe the answer is:
ochre
'colour' is the definition.
(I know that ochre is a type of earth color)
'exclamation of scot about' is the wordplay.
I cannot really see how this works, but
'exclamation' could be 'och' (I have seen 'Scots exclamation ' mean 'och' so perhaps 'exclamation' could also mean 'och') and 'och' is found in the answer.
'about' could be 're' ('re' means regarding or about) and 're' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ochre that I've seen before include "Chore using pale brownish colour (5)" , "Light yellow-brown colour" , "Money" , "Yellow-orange hue" , "Gold coins, perhaps" .)