British surgeon's bubble (7)
I believe the answer is:
blister
'bubble' is the definition.
(thesaurus)
'british surgeon's' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'surgeon' becomes 'Lister' (Joseph Lister, father of modern surgery).
'b'+'lister'='BLISTER'
(Other definitions for blister that I've seen before include "Bubble-like swelling on skin" , "Bubble on the skin filled with fluid" , "Bubble raised on the skin" , "Effect of rubbing on skin" , "Sore bubble on skin" .)