Harrowing neck torture (5-7)
I believe the answer is:
nerve-racking
'harrowing' is the definition.
(I've seen this before)
'neck torture' is the wordplay.
'neck' becomes 'nerve' (both can mean attitude or insolence).
'torture' becomes 'racking' (torturing someone on a rack).
'nerve'+'racking'='NERVE-RACKING'
(Other definitions for nerve-racking that I've seen before include "Stressful" , "Harrowing" , "Causing great anxiety" .)