Sick-looking friend needing cover (6)
I believe the answer is:
pallid
'sick-looking' is the definition.
(pallid means sickly or pale)
'friend needing cover' is the wordplay.
'friend' becomes 'pal' (pal can mean a friend).
'needing' is a charade indicator (letters next to each other).
'cover' becomes 'lid' (lid is a kind of cover).
'pal'+'lid'='PALLID'
(Other definitions for pallid that I've seen before include "White in face as from illness" , "Sickly pale" , "White in face, perhaps ill" , "Pale, insipid" , "Pale complexion because of poor health" .)