Designer of bow affected by shocking treatment (9)
I believe the answer is:
architect
'designer' is the definition.
('architect' can be a synonym of 'designer')
'bow affected by shocking treatment' is the wordplay.
'bow' becomes 'arc' ('arc' can be a synonym of 'bow').
'affected by' becomes 'hit'.
'shocking treatment' becomes 'ect' (electro-convulsive therapy).
'arc'+'hit'+'ect'='ARCHITECT'
'of' acts as a link.
(Other definitions for architect that I've seen before include "professional" , "Designer of buildings" , "Wren perhaps" , "Building designer" , "Author" .)