Ban this crook liquor (7)
I believe the answer is:
'liquor' is the definition.
(absinth is a kind of liquor)
'ban this crook' is the wordplay.
'crook' is an anagram indicator (a crooked or broken form of the letters).
'banthis' is an anagram of 'ABSINTH'.
(Other definitions for absinth that I've seen before include "sort of liqueur", "(Originally) a wormwood-based liqueur", "Aniseed-flavoured liqueur", "Strong liqueur with wormwood and anise", "Shrubby plant".)