Bit of a shock, economist's solution to key problem (9)
I believe the answer is:
locksmith
'solution to key problem' is the definition.
(a locksmith might resolve a lock or key problem)
'bit of a shock economist's' is the wordplay.
'bit of a shock' becomes 'lock' (shock can mean a mass of hair).
'economist' becomes 'Smith' (18th-century economist Adam Smith).
'lock'+'smith'='LOCKSMITH'
(Other definitions for locksmith that I've seen before include "Security device maker" , "Maker of secure fasteners" , "Yale scholar" , "Security expert" , "Maker of security devices" .)