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