Get back on with putsch (6)
I believe the answer is:
recoup
'get back' is the definition.
(I've seen this before)
'on with putsch' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'with' means one lot of letters go next to another.
'putsch' becomes 'coup' (synonyms).
're'+'coup'='RECOUP'
(Other definitions for recoup that I've seen before include "Get back (outlay)" , "Get back one's losses" , "Regain a loss through subsequent profits" , "make good one's losses" , "Regain (something lost)" .)