Georgia possibly claiming Union is bust? (6)
I believe the answer is:
statue
'is bust?' is the definition.
(type of statue)
'georgia possibly claiming union' is the wordplay.
'georgia possibly' becomes 'state' (Georgia is a US state).
'claiming' means one lot of letters goes inside another.
'union' becomes 'U' (common abbreviation as in 'Trades Union Congress').
'state' going around 'u' is 'STATUE'.
(Other definitions for statue that I've seen before include "With which Bartholdi achieved eminence" , "Carved or cast figure" , "Sculpture depicting a person" , "Sculptured likeness" , "Firm figure" .)