He trades in new ways to demoralise (10)
I believe the answer is:
dishearten
'to demoralise' is the definition.
(thesaurus)
'he trades in new ways' is the wordplay.
'new ways' indicates an anagram (I've seen 'new way' mean this).
'he'+'trades'+'in'='hetradesin'
'hetradesin' is an anagram of 'DISHEARTEN'.
(Other definitions for dishearten that I've seen before include "dismay?" , "cast down" , "Cause (someone) to lose confidence" , "Bring down" , "Take away bottle" .)