E European going places promoting son (4)
I believe the answer is:
slav
'e european' is the definition.
(Slavs are an Eastern European people)
I can't explain the rest of the clue.
(Other definitions for slav that I've seen before include "One of the European people" , "East European - Asian Russian" , "Native of eastern Europe or northwestern Asia" , "A Russian, say" , "Eastern European" .)