The shape of Kennington (4)
I believe the answer is:
oval
'the shape' is the definition.
(oval is a kind of shape)
'of kennington' is the wordplay.
'of' becomes 'o''.
'kennington' becomes 'val' (I can't explain this - if you can you should give a lot more credence to this answer).
'o'+'val'='OVAL'
Can you help me to learn more?
(Other definitions for oval that I've seen before include "London cricket ground" , "Egg shape, roughly" , "Egg-shaped - cricket ground" , "Shape of 25" , "sports ground" .)