Split in putsch is magnified (6)
I believe the answer is:
schism
'split' is the definition.
('schism' can be a synonym of 'split')
'in putsch is magnified' is the wordplay.
'in' indicates a hidden word.
'SCHISM' is hidden within 'putsch is magnified'.
(Other definitions for schism that I've seen before include "Split over doctrinal beliefs" , "Breach within a church organisation" , "Breach or split in a church" , "Split in church unity" , "Split, often ecclesiastical" .)