Claret's odd colour (7)
I believe the answer is:
scarlet
'colour' is the definition.
(I know that scarlet is a colour)
'claret's odd' is the wordplay.
'odd' indicates an anagram.
'clarets' anagrammed gives 'SCARLET'.
(Other definitions for scarlet that I've seen before include "Bright red of clarets" , "Fallen" , "Red colour of clarets" , "Cherry-red" , "Murderer" .)