A communist leader left about nine (5)
I believe the answer is:
lenin
'a communist leader' is the definition.
(I've seen this in another clue)
'left about nine' is the wordplay.
'left' becomes 'l' (common abbreviation).
'about' indicates an anagram.
'nine' with letters rearranged gives 'enin'.
'l'+'enin'='LENIN'
(Other definitions for lenin that I've seen before include "Vladimir Ilyich Ulyanov, d. 1924" , "Linen for Communist" , "Head of the Communist state after the fall of the Tsar" , "Vladimir Ilyich -, Soviet premier" , "Russian revolutionary" .)