Looks a bit sick due to quiet drinks (5)
I believe the answer is:
pales
'looks a bit sick due' is the definition.
Although both the answer and definition are verbs in their -s form, I can't understand how they can define each other.
'quiet drinks' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano', ie soft or quiet).
'drinks' becomes 'ales' (ale is a kind of drink).
'p'+'ales'='PALES'
'to' is the link.
Can you help me to learn more?
(Other definitions for pales that I've seen before include "Goes white, loses colour" , "Goes white in leaps" .)