Director put to death with intravenous injection (9)
I believe the answer is:
executive
'director' is the definition.
(thesaurus)
'put to death with intravenous injection' is the wordplay.
'put to death' becomes 'execute' ('execute' can be a synonym of 'put to death').
'with' means one lot of letters goes inside another.
'intravenous injection' becomes 'iv'.
'execute' placed around 'iv' is 'EXECUTIVE'.
(Other definitions for executive that I've seen before include "boss" , "Person who makes and carries out decisions" , "power to administer" , "Supervisory - manager" , "Administrator, manager" .)