Form new heaps (5)
I believe the answer is:
shape
'form' is the definition.
(synonyms)
'new heaps' is the wordplay.
'new' indicates an anagram.
'heaps' with letters rearranged gives 'SHAPE'.
(Other definitions for shape that I've seen before include "Mould into new phase" , "Form; mould" , "Phase (anag.)" , "Form, figure" , "Square, circle, etc." .)