Russian, perhaps, one with leading position (4)
I believe the answer is:
ivan
'russian' is the definition.
(common Russian name)
'one with leading position' is the wordplay.
'one' becomes 'i' (Roman numeral).
'with' says to put letters next to each other.
'leading position' becomes 'van' (term for the front of a group eg a military group).
'i'+'van'='IVAN'
'perhaps' acts as a link.
(Other definitions for ivan that I've seen before include "Russian tsar called 'the Terrible'" , "Tsar - 197> the Terrible" , "man who had a terrible reputation" , "Russian ruler - a Terrible one" , "- - the Terrible (Czar)" .)