Breaking this bottle could be a facer! (6)
I believe the answer is:
carafe
'breaking this bottle' is the definition.
'carafe' can be an answer for 'bottle' (carafe is a kind of bottle). I'm not certain of the rest of the definition.
'could be a facer' is the wordplay.
'could be' is an anagram indicator.
'a'+'facer'='afacer'
'afacer' is an anagram of 'CARAFE'.
Can you help me to learn more?
(Other definitions for carafe that I've seen before include "Wine is decanted into it" , "keeper of wine" , "Decanter" , "Table container for wine" , "Wine-flask" .)