Autonomy, then, is partly a fable? (4)
I believe the answer is:
myth
'a fable?' is the definition.
(I've seen this before)
'autonomy then is partly' is the wordplay.
'is partly' indicates the answer is hidden within the clue (part of the clue is used).
'MYTH' can be found hidden inside 'autonomy then'.
(Other definitions for myth that I've seen before include "Fancy" , "Traditional story not based on fact" , "Delusion" , "Unfounded belief" , "Traditional allegory" .)