A married woman in the USA (7)
I believe the answer is:
america
'the usa' is the definition.
(synonyms)
'a married woman' is the wordplay.
'married' becomes 'm' (abbreviation, e.g. in genealogy).
'woman' becomes 'erica' ().
'a'+'m'+'erica'='AMERICA'
'in' acts as a link.
(Other definitions for america that I've seen before include "'Country named after Vespucci, Italian navigator (7)'" , "country targeted by 3 [ROMNEY]" , "Song title shared by Sondheim-Bernstein and Paul Simon among others" , "Continent of the Western Hemisphere" , "United States" .)