Fat politician consumed by booze (5)
I believe the answer is:
ample
'fat' is the definition.
(thesaurus)
'politician consumed by booze' is the wordplay.
'politician' becomes 'MP' (Member of Parliament).
'consumed by' means one lot of letters goes inside another (inserted letters get consumed).
'booze' becomes 'ale' (type of alcohol).
'mp' placed inside 'ale' is 'AMPLE'.
(Other definitions for ample that I've seen before include "Fully enough" , "Copious - abundant" , "Plentiful, quite enough" , "Sealed glass container for dose of medicine" , "Full-figured" .)