Panic gripping posh model? (6)
I believe the answer is:
statue
'model?' is the definition.
(thesaurus)
'panic gripping posh' is the wordplay.
'panic' becomes 'state' (I've seen this in other clues**).
'gripping' indicates putting letters inside.
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-u).
'state' placed around 'u' is 'STATUE'.
(Other definitions for statue that I've seen before include "A carved or sculpted figure" , "Solid representation of the human form" , "Figurative sculpture" , "permanent fixture" , "Noble's rank or dignity" .)