So accustomed to being drunk? (6)
I believe the answer is:
soused
'being drunk?' is the definition.
(thesaurus)
'so accustomed' is the wordplay.
'accustomed' becomes 'used' (I've seen this before).
'so'+'used'='SOUSED'
'to' acts as a link.
(Other definitions for soused that I've seen before include "Soaked, pickled (gherkin); drunk (colloq.)" , "Drenched with liquid" , "Drunk or immersed in liquid" , "Marinated" .)