In pub, drunk loves starting with tequila on the rocks (9)
I believe the answer is:
insolvent
'on the rocks' is the definition.
(thesaurus)
'in pub drunk loves starting with tequila' is the wordplay.
'in' is an insertion indicator.
'pub' becomes 'inn' (I've seen this before).
'drunk' is an anagram indicator.
'starting with' indicates taking the first letters.
The first letter of 'tequila' is 't'.
'loves' is an anagram of 'solve'.
'inn' enclosing 'solve' is 'insolven'.
'insolven'+'t'='INSOLVENT'
(Other definitions for insolvent that I've seen before include "Unable to pay debts owed" , "Snivel not, although you are bankrupt!" , "Gone bust, without a bean" , "strapped for cash" , "deep in debt?" .)