Condemn study on wild cat (8)
I believe the answer is:
denounce
'condemn' is the definition.
(I know that condemn is a more specific form of the action denounce)
'study on wild cat' is the wordplay.
'study' becomes 'den' (term for a study or office).
'on' means one lot of letters go next to another.
'wild cat' becomes 'ounce' (I've seen this before).
'den'+'ounce'='DENOUNCE'
(Other definitions for denounce that I've seen before include "Openly deplore" , "Speak publicly or give information against" , "Openly condemn" , "Condemn or censure" , "Speak publicly against, expose" .)