Set out to stop honest administrator (7)
I believe the answer is:
trustee
'administrator' is the definition.
(type of administrator of a trust)
'set out to stop honest' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'to stop' is an insertion indicator (stopping can mean blocking a gap).
'honest' becomes 'true' (associated in meaning).
'set' anagrammed gives 'ste'.
'ste' inserted within 'true' is 'TRUSTEE'.
(Other definitions for trustee that I've seen before include "Member of a fund's governing board" , "Legal guardian" , "Legal administrator" , "Person who holds and administers property for another - sounds reliable" , "financial overseer" .)