Staff taken aback about City ornamentation (5)
I believe the answer is:
decor
'ornamentation' is the definition.
(I know that decor is a type of ornamentation)
'staff taken aback about city' is the wordplay.
'staff' becomes 'rod' (both can mean a stick or cane).
'taken aback' says the letters should be written backwards.
'about' means one lot of letters goes inside another.
'city' becomes 'EC' (the City of London postcode).
'rod' reversed gives 'dor'.
'dor' going around 'ec' is 'DECOR'.
(Other definitions for decor that I've seen before include "Room colour scheme, furnishings, etc" , "furnishings required" , "Colour-scheme etc of a room" , "stage background" , "Internal ornamentation" .)