Utter depravity gripping the stony-hearted (5)
I believe the answer is:
voice
'utter' is the definition.
(I know that voice is a type of utter)
'depravity gripping the stony-hearted' is the wordplay.
'depravity' becomes 'vice' (I've seen this before).
'gripping' is an insertion indicator.
'hearted' says to take the centre.
The central letter of 'stony' is 'o'.
'vice' going around 'o' is 'VOICE'.
(Other definitions for voice that I've seen before include "tenor, say" , "right to have a say" , "Computerised analysis of speech" , "Opinion; express in words" , "Sound produced by humans" .)