Model upstart lying in state (6)
I believe the answer is:
statue
'model' is the definition.
(thesaurus)
'upstart lying in state' is the wordplay.
'upstart' becomes 'u' (start of the word 'up').
'lying in' is an insertion indicator.
'u' placed within 'state' is 'STATUE'.
(Other definitions for statue that I've seen before include "One representing liberty" , "Large figure" , "A carved or sculpted figure" , "Piece of sculpture" , "Monument" .)