Start to live on booze (5)
I believe the answer is:
begin
'start' is the definition.
(I know that start can be written as begin)
'live on booze' is the wordplay.
'live' becomes 'be' (synonyms).
'on' means one lot of letters go next to another.
'booze' becomes 'gin' (gin is a kind of booze).
'be'+'gin'='BEGIN'
'to' is the link.
(Other definitions for begin that I've seen before include "Partly open" , "Israeli prime minister and Nobel Peace Prize winner, d. 1992" , "Get cracking" , "former Israeli Nobel peace prize winner" , "Israeli statesman" .)