Spy arresting Republican in a South American country (9)
I believe the answer is:
argentina
'south american country' is the definition.
(Argentina is an example)
'spy arresting republican in a' is the wordplay.
'spy' becomes 'agent' (I've seen this before**).
'arresting' means one lot of letters goes inside another.
'republican' becomes 'r' (abbreviation).
'agent' placed around 'r' is 'argent'.
'argent'+'in'+'a'='ARGENTINA'
(Other definitions for argentina that I've seen before include "Republic" , "state" , "An ingrate in S American country" , "FIFA World Cup winners in 1978 and 1986" , "part of 18 [SOUTH AMERICA]" .)