Sweet Fanny Adams upsetting pack animal engenders sanction (4)
I believe the answer is:
okay
'sanction' is the definition.
(okay is a kind of sanction)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for okay that I've seen before include "Fairly good; approve" , "Leave" , "Agreed!" , "Common jargon for yes, all right" , "Permissible; fairly good" .)