Part of the foot of the elephant (4)
I believe the answer is:
heel
'part of the foot' is the definition.
(I've seen this before)
'of the elephant' is the wordplay.
'of' indicates the answer is hidden within the clue.
'HEEL' can be found hidden inside 'the elephant'.
(Other definitions for heel that I've seen before include "secure ball" , "site of Achilles' downfall?" , "Reprehensible person" , "order to dog" , "scumbag" .)