Greek heart of razorback (5)
I believe the answer is:
'greek heart' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'of razorback' is the wordplay.
'of' says the answer is hidden in the clue.
'ZORBA' can be found hidden inside 'razorback'.
Can you help me to learn more?
(Other definitions for zorba that I've seen before include "Greek film character" , "Anthony Quinn's Greek" , "Greek dancer (film)" .)