One knowing nothing of what Signora Mussolini is concealing (9)
I believe the answer is:
ignoramus
'one knowing nothing' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'what signora mussolini is concealing' is the wordplay.
'is concealing' says the answer is hidden in the clue.
'IGNORAMUS' is hidden within 'what signora mussolini'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for ignoramus that I've seen before include "Dunce" , "One lacking knowledge" , "A know-nothing" , "One is not intelligent" , "one in a state of bliss?" .)