District in Far East (4)
I believe the answer is:
area
'district' is the definition.
(thesaurus)
'in far east' is the wordplay.
'in' indicates the answer is hidden within the clue.
'AREA' is hidden within 'far east'.
(Other definitions for area that I've seen before include "Field of activity or surface" , "Speaking formally to (someone)" , "Patch" , "'Tract, region (4)'" , "District; locale" .)