Wind-player popular when in drink (8)
I believe the answer is:
clarinet
'wind' is the definition.
(clarinet is a kind of wind)
'popular when in drink' is the wordplay.
'popular' becomes 'in' (something that's 'in' is fashionable).
'when in' means one lot of letters goes inside another.
'drink' becomes 'claret' (claret is a kind of drink).
'in' going inside 'claret' is 'CLARINET'.
'player' acts as a link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for clarinet that I've seen before include "Woodwind instrument played by Artie Shaw and Benny Goodman" , "musician" , "23 instrument" , "Blow that!" , "Find an instrument in claret" .)