Short headstrong Russian leader and svengali (8)
I believe the answer is:
rasputin
'svengali' is the definition.
(thesaurus)
'short headstrong russian leader' is the wordplay.
'short' means to remove the last letter.
'headstrong' becomes 'rash' (I've seen this before).
'russian leader' becomes 'putin' (Vladimir Putin).
'rash' with its last letter removed is 'ras'.
'ras'+'putin'='RASPUTIN'
'and' acts as a link.
(Other definitions for rasputin that I've seen before include "Peasant monk" , "Sinister adviser" , "Notorious Russian monk embraced by puritans" , "Puritans (anag) - Russian monk" , "Old courtier" .)