Nothing in fact is drunk in the party (7)
I believe the answer is:
faction
'party' is the definition.
(thesaurus)
'nothing in fact is drunk in' is the wordplay.
'nothing' becomes 'O' (looks like zero - 0).
'is drunk' is an anagram indicator.
'in' is an insertion indicator.
'in'+'fact'='infact'
'infact' anagrammed gives 'factin'.
'o' inserted within 'factin' is 'FACTION'.
'the' is the link.
(Other definitions for faction that I've seen before include "Small trouble-making group within a group" , "Rebellious group" , "Wing" , "Clique that seeks power often through intrigue" , "A dissenting clique" .)