Demonstrate capturing fine badger (7)
I believe the answer is:
provoke
'badger' is the definition.
(thesaurus)
'demonstrate capturing fine' is the wordplay.
'demonstrate' becomes 'prove' (synonyms).
'capturing' means one lot of letters goes inside another.
'fine' becomes 'ok' (synonyms).
'prove' placed around 'ok' is 'PROVOKE'.
(Other definitions for provoke that I've seen before include "Stimulate (a reaction)" , "needle" , "Irritate - arouse" , "Make angry or incite to action" , "Incense" .)