Country having a thousand Polish perhaps returning (5)
I believe the answer is:
burma
'country' is the definition.
(Burma is an example)
'a thousand polish perhaps returning' is the wordplay.
'thousand' becomes 'm' (synonyms).
'polish perhaps' becomes 'rub' (polish can mean to rub to make shiny).
'returning' says the letters should be written backwards.
'a'+'m'+'rub'='amrub'
'amrub' back-to-front is 'BURMA'.
'having' acts as a link.
(Other definitions for burma that I've seen before include "Rumba (anag)" , "Country also known as Myanmar" , "Country of SE Asia" , "Union of Myanmar" , "Alternative name for Myanmar" .)