Cleric receiving East European magistrate (5)
I believe the answer is:
reeve
'magistrate' is the definition.
(I've seen this before)
'cleric receiving east european' is the wordplay.
'cleric' becomes 'rev' (abbreviation for Reverend).
'receiving' means one lot of letters goes inside another.
'east' becomes 'e' ('E' can be a synonym of 'east').
'european' becomes 'e' (abbreviation e.g. EU).
'rev' placed around 'e' is 'reev'.
'reev'+'e'='REEVE'
(Other definitions for reeve that I've seen before include "Medieval official - pass rope through an eye" , "Anglo-Saxon magistrate - female bird - pass (a rope) through a hole" , "One of Chaucer's tale-tellers" , "Former official - female ruff" , "One of Chaucer's Canterbury pilgrims" .)