Reveal former model (6)
I believe the answer is:
expose
'reveal' is the definition.
(I know that reveal can be written as expose)
'former model' is the wordplay.
'former' becomes 'ex' (prefix meaning former or onetime).
'model' becomes 'pose' (model can mean to pose).
'ex'+'pose'='EXPOSE'
(Other definitions for expose that I've seen before include "Reveal or unmask" , "Make visible or apparent" , "Uncover or unmask" , "brings out crime" , "Show up" .)