Start carving stone (5)
I believe the answer is:
onset
'start' is the definition.
(both can mean the beginning of something)
'carving stone' is the wordplay.
'carving' is an anagram indicator.
'stone' with letters rearranged gives 'ONSET'.
(Other definitions for onset that I've seen before include "Beginning; violent attack" , "Advent" , "Beginning or early stages" , "Start, beginning" , "Beginning (of something often unpleasant)" .)