Condemn fool holding figure upside down (8)
I believe the answer is:
denounce
'condemn' is the definition.
(I've seen this before)
'fool holding figure upside down' is the wordplay.
'fool' becomes 'dunce' (both can mean a stupid person).
'holding' is an insertion indicator.
'figure' becomes 'one' (a numerical figure).
'upside down' is a reversal indicator.
'one' back-to-front is 'eno'.
'dunce' enclosing 'eno' is 'DENOUNCE'.
(Other definitions for denounce that I've seen before include "Condemn or censure" , "Criticise or condemn" , "As threat, identify" , "Rubbish" , "Hit out at" .)