Former politician embraces one extremely lithe model (7)
I believe the answer is:
example
'model' is the definition.
('example' can be a synonym of 'model')
'former politician embraces one extremely lithe' is the wordplay.
'former' becomes 'ex'.
'politician' becomes 'mp'.
'embraces' is an insertion indicator.
'one' becomes 'a'.
'extremely' suggests removing the centre.
'lithe' with its middle taken out is 'le'.
'ex'+'mp'='exmp'
'exmp' placed around 'a' is 'examp'.
'examp'+'le'='EXAMPLE'
(Other definitions for example that I've seen before include "Illustration or model" , "Specimen, illustration" , "Characteristic item" , "Illustration or paradigm" , "Model - instance" .)