English playwright sure to leave university (4)
I believe the answer is:
bond
'english playwright' is the definition.
(playwright Edward Bond)
'sure to leave university' is the wordplay.
'sure' becomes 'bound' (synonyms).
'to leave' suggests deleting specific letters.
'university' becomes 'u' (abbreviation for university).
'bound' with 'u' taken out is 'BOND'.
(Other definitions for bond that I've seen before include "Valuable asset" , "Obligation" , "Financial asset" , "Luxury shopping area in central London" , "Certificate of debt" .)