Gross politician, one found in boozer (7)
I believe the answer is:
lumpish
'gross' is the definition.
(thesaurus)
'politician one found in boozer' is the wordplay.
'politician' becomes 'MP' (Member of Parliament).
'one' becomes 'i' (Roman numeral).
'found in' is an insertion indicator.
'boozer' becomes 'lush' (synonyms).
'mp'+'i'='mpi'
'mpi' placed inside 'lush' is 'LUMPISH'.
(Other definitions for lumpish that I've seen before include "Ungainly" , "misshapen" .)