Bad smell in small English boozer (6)
I believe the answer is:
sponge
'boozer' is the definition.
(thesaurus)
'bad smell in small english' is the wordplay.
'bad smell' becomes 'pong' (informal term).
'in' is an insertion indicator.
'small' becomes 's' (abbreviation - e.g. clothes size).
'english' becomes 'e' (abbreviation).
's'+'e'='se'
'pong' placed into 'se' is 'SPONGE'.
(Other definitions for sponge that I've seen before include "Animal that absorbs liquid" , "Piece of porous rubber" , "Sea animal often found in bath" , "Wipe" , "Scrounge; wiper" .)