Missionary agents live abroad (10)
I believe the answer is:
evangelist
'missionary' is the definition.
('evangelist' can be a synonym of 'missionary')
'agents live abroad' is the wordplay.
'abroad' is an anagram indicator.
'agents'+'live'='agentslive'
'agentslive' is an anagram of 'EVANGELIST'.
(Other definitions for evangelist that I've seen before include "Gospel writer" , "Zealous believer" , "Zealous advocate" , "Preacher" , "Gospel spreader" .)