Mould or model (5)
I believe the answer is:
shape
I believe this clue is a double definition.
'mould' is the first definition.
(I know that mould can be written as shape)
'model' is the second definition.
(thesaurus)
(Other definitions for shape that I've seen before include "Mould into new phase" , "Form; mould" , "Good physical form" , "For good physical condition" , "Square, circle, etc." .)