An Italian component of necromancy (5)
I believe the answer is:
roman
'an italian' is the definition.
(someone from Rome)
'component of necromancy' is the wordplay.
'component of' indicates a hidden word (I've seen this in other clues).
'ROMAN' can be found hidden inside 'necromancy'.
(Other definitions for roman that I've seen before include "Plain upright type" , "of foreign city" , "Plain upright print style" , "Upright form of type" , "(Of a nose) high-bridged" .)