Passing remarks about Republican circle (5)
I believe the answer is:
orbit
'circle' is the definition.
(I know that orbit is a more specific form of the action circle)
'passing remarks about republican' is the wordplay.
'passing remarks' becomes 'obit' (obituary, report on someone's passing).
'about' is an insertion indicator.
'republican' becomes 'r' (abbreviation).
'obit' going around 'r' is 'ORBIT'.
(Other definitions for orbit that I've seen before include "Path of planet around sun" , "Rotating path" , "Revolve round" , "Path of one celestial body around another" , "Area of influence - eye socket" .)