Blockhead in Obama's shoes (3)
I believe the answer is:
ass
'blockhead' is the definition.
(I've seen this before)
'in obama's shoes' is the wordplay.
'in' indicates a hidden word.
'ASS' is hidden in the letters of 'obamas shoes'.
(Other definitions for ass that I've seen before include "Horse relative" , "slow-witted person" , "Wally" , "jack" , "Dipstick" .)