Ingenuous doctor autopsied snitch (15)
I believe the answer is:
unsophisticated
'ingenuous' is the definition.
(I've seen this in another clue)
'doctor autopsied snitch' is the wordplay.
'doctor' is an anagram indicator.
'autopsied'+'snitch'='autopsiedsnitch'
'autopsiedsnitch' is an anagram of 'UNSOPHISTICATED'.
(Other definitions for unsophisticated that I've seen before include "crude" , "green" , "straightforward" , "Lacking experience" , "Simple" .)