Republican in Polish tomb (6)
I believe the answer is:
shrine
'tomb' is the definition.
(thesaurus)
'republican in polish' is the wordplay.
'republican' becomes 'r' (abbreviation).
'in' is an insertion indicator.
'polish' becomes 'shine' (synonyms).
'r' placed inside 'shine' is 'SHRINE'.
(Other definitions for shrine that I've seen before include "Container for sacred relics" , "here to pray?" , "Hallowed place with religious association (6)" , "Hallowed place associated with a sacred thing or person" , "Holy site of relics etc" .)