Drunk? That half-cut swine flipping is! (5)
I believe the answer is:
tight
'drunk? that half-cut swine flipping is' is the definition.
'tight' can be an answer for 'drunk?' (slang term). I'm unsure of the remainder of the definition.
'drunk? that half-cut' is the wordplay.
'drunk?' becomes 'tig' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'half' suggests halving the letters.
'cut' is an anagram indicator (cut can mean mixed).
'that' cut in half is 'th'.
'th' is an anagram of 'ht'.
'tig'+'ht'='TIGHT'
Can you help me to learn more?
(Other definitions for tight that I've seen before include "Trim" , "Drunk; giving little room" , "Firmly fastened; tense" , "Parsimonious" , "Stretched" .)