Foreign mission (7)
I believe the answer is:
embassy
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">foreign mission</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for embassy that I've seen before include "Overseas mission" , "Ambassador's office" , "Residence of an ambassador" , "Diplomatic office or residence." , "Consulate" .)