Jock's exclamation about a particular colour (5)
I believe the answer is:
ochre
'a particular colour' is the definition.
(ochre is a colour)
'jock's exclamation about' is the wordplay.
I cannot quite understand 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 within the answer.
'about' could be 're' (regarding) and 're' is found in the answer.
No letters remain.
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 "Yellow/brown/red pigment" , "Pigment made from clay and iron oxide" , "Yellow-red mineral from iron oxide used as pigment" , "Mineral pigment; chore (anag.)" , "Yellow-orange hue" .)