Exclude East German breed taking lead in Crufts? (9)
I believe the answer is:
ostracise
'exclude' is the definition.
(ostracising is a kind of excluding)
'east german breed taking lead in crufts?' is the wordplay.
'east german' becomes 'ost' ('east' in German).
'breed' becomes 'raise' (I've seen this in another clue).
'taking' is an insertion indicator.
'lead in' suggests taking the first letters.
The initial letter of 'crufts' is 'c'.
'raise' placed around 'c' is 'racise'.
'ost'+'racise'='OSTRACISE'
(Other definitions for ostracise that I've seen before include "I, Socrates may exclude from group" , "exile" , "Banish from group" , "Banish, blackball" , "Cast out, send to Coventry" .)