Claret's changed colour (7)
I believe the answer is:
scarlet
'colour' is the definition.
(scarlet is a kind of colour)
'claret's changed' is the wordplay.
'changed' is an anagram indicator.
'clarets' with letters rearranged gives 'SCARLET'.
(Other definitions for scarlet that I've seen before include "Crimson" , "immoral" , "Shade of red" , "Murderer" , "Bright red of clarets" .)