Fight about retro tool (7)
I believe the answer is:
scraper
'tool' is the definition.
(scraper is a kind of tool)
'fight about retro' is the wordplay.
'fight' becomes 'scrap' (I've seen this before).
'about' becomes 're' (common abbreviation for 'with reference to').
'retro' is a reversal indicator (retro is Latin for 'backwards').
're' written backwards gives 'er'.
'scrap'+'er'='SCRAPER'
(Other definitions for scraper that I've seen before include "Hand tool for clearing surfaces" , "Tool for removing, eg, dirt or paint" , "Violinist" , "Economist?" , "Surface-cleaning tool" .)