Looking wan, you need a quiet drink (4)
I believe the answer is:
pale
'looking wan you need' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'a quiet drink' is the wordplay.
'a quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'drink' becomes 'ale' (type of beer).
'p'+'ale'='PALE'
Can you help me to learn more?
(Other definitions for pale that I've seen before include "Colourless" , "White" , "Having less colour than normal" , "Stake, lacking colour" , "wooden post" .)