Row about Italian revolutionary (4)
I believe the answer is:
tier
'row' is the definition.
(a tier is a row of things)
'about italian revolutionary' is the wordplay.
'about' becomes 're' ('re' means regarding or about).
'italian' becomes 'it' (common abbreviation).
'revolutionary' says the letters should be written backwards (letters revolve around).
're'+'it'='reit'
'reit' backwards is 'TIER'.
(Other definitions for tier that I've seen before include "One securing" , "Rite about layer" , "one doing Bond" , "Row, layer" , "Row (of seats)" .)