English impertinence: every individual pinches Frenchman’s bottom! (9)
I believe the answer is:
sassenach
'english' is the definition.
(I've seen this before)
'impertinence every individual pinches frenchman's bottom' is the wordplay.
'impertinence' becomes 'sass' (sass is a kind of impertinence).
'every individual' becomes 'each' (I've seen this before).
'pinches' is an insertion indicator (pinch can mean to steal).
'bottom' says to take the final letters.
The last letter of 'frenchman' is 'n'.
'each' placed around 'n' is 'enach'.
'sass'+'enach'='SASSENACH'
(Other definitions for sassenach that I've seen before include "Englishman in Scotland" , "Lowland Scot" , "Englishman, Lowlander" , "Uncomplimentary Scots term for an Englishman" , "In Scotland, English" .)