An orderly area of the UK (6)
I believe the answer is:
antrim
'area of the uk' is the definition.
(county of Northern Ireland)
'an orderly' is the wordplay.
'orderly' becomes 'trim' (synonyms).
'an'+'trim'='ANTRIM'
(Other definitions for antrim that I've seen before include "NI county" , "Giant's Causeway county" , "Ulster county" , "NI town" , "town in Ireland" .)