Possibly withered, not red but pallid (5)
I believe the answer is:
white
'pallid' is the definition.
(I've seen this before)
'possibly withered not red' is the wordplay.
'possibly' indicates an anagram.
'not' is a deletion indicator.
'withered' with 'red' taken out is 'withe'.
'withe' anagrammed gives 'WHITE'.
'but' is the link.
(Other definitions for white that I've seen before include "- Christmas, famous song" , "Wit, he? (anag.)" , "Colourless" , "Neutral colour" , "wine" .)