Member of the San Francisco police (3)
I believe the answer is:
cop
'member' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'of the san francisco police' is the wordplay.
'of' indicates a hidden word.
'COP' can be found hidden inside 'san francisco police'.
Can you help me to learn more?
(Other definitions for cop that I've seen before include "Short policeman" , "Policeman (informal)" , "Policeman (slang)" , "catch" , "An American policeman" .)