Outlaw coffee? It sounds horrible! (5)
I believe the answer is:
banjo
'it sounds horrible' is the definition.
The definition suggests a singular noun which matches the answer.
'outlaw coffee?' is the wordplay.
'outlaw' becomes 'ban' (banning is a kind of outlawing).
'coffee?' becomes 'jo' (I can't justify this - if you can you should believe this answer much more).
'ban'+'jo'='BANJO'
Can you help me to learn more?
(Other definitions for banjo that I've seen before include "Bluegrass instrument?" , "strumming instrument" , "Long-necked instrument" , "Stringed instrument beloved of old minstrel shows" , "Five-stringed musical instrument" .)