Au naturel or largely under cooked (4)
I believe the answer is:
nude
'au naturel' is the definition.
(I know that au naturel can be written as nude)
'largely under cooked' is the wordplay.
'largely' means to remove the last letter.
'cooked' indicates an anagram (letters cooked into a new form).
'under' with its final letter taken off is 'unde'.
'unde' anagrammed gives 'NUDE'.
'or' is the link.
(Other definitions for nude that I've seen before include "not in gear" , "Wearing no clothes" , "Naked person" , "totally exposed" , "lacking cover" .)