Republican returning to university here in South America (4)
I believe the answer is:
peru
'here in south america' is the definition.
'republican returning to university' is the wordplay.
'republican' becomes 'rep'.
'returning' says the letters should be written in reverse.
'to university' becomes 'u'.
'rep' back-to-front is 'per'.
'per'+'u'='PERU'
(Other definitions for peru that I've seen before include "Machu Picchu country" , "Homeland of Paddington Bear" , "Mario Vargas Llosa's native land" , "South American republic" , "Lima's country" .)