Whiteness of cloud tipped with gold (6)
I believe the answer is:
pallor
'whiteness' is the definition.
(I've seen this in another clue)
'cloud tipped with gold' is the wordplay.
'cloud' becomes 'pall' (I've seen this in another clue).
'tipped with' is a charade indicator (letters next to each other) (some letters go on the tip or end of others).
'gold' becomes 'or' ('or' is the heraldic name for gold).
'pall'+'or'='PALLOR'
'of' is the link.
(Other definitions for pallor that I've seen before include "Unnatural whiteness" , "Ashen complexion due to illness" , "Unnatural lack of colour in the skin" , "Whiteness of face as from illness" , "Unhealthy whiteness" .)