Shock old doctor, quietly, during call (9)
I believe the answer is:
bombshell
'shock' is the definition.
(bombshell can mean a great shock)
'old doctor quietly during call' is the wordplay.
'old doctor' becomes 'omb' (I am not sure about this - if you are sure you should believe this answer much more).
'quietly' becomes 'sh' (both are used to tell someone to be quiet).
'during' indicates putting letters inside.
'call' becomes 'bell' (bell can mean a phone call).
'omb'+'sh'='ombsh'
'ombsh' placed into 'bell' is 'BOMBSHELL'.
Can you help me to learn more?
(Other definitions for bombshell that I've seen before include "attractive blonde" , "awful surprise" , "Unpleasant surprise" , "big disappointment" , "Overwhelming surprise" .)