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' is an anagram indicator.
'not' suggests deleting specific letters.
'withered' with 'red' taken out is 'withe'.
'withe' is an anagram of '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" .)