Disobedient in playing outside barn (13)
I believe the answer is:
insubordinate
'disobedient' is the definition.
('insubordinate' can be similar in meaning to 'disobedient')
'in playing outside barn' is the wordplay.
'playing' indicates an anagram.
'outside'+'barn'='outsidebarn'
'outsidebarn' with letters rearranged gives 'subordinate'.
'in'+'subordinate'='INSUBORDINATE'
(Other definitions for insubordinate that I've seen before include "Cheeky" , "Defiant of authority" , "Recalcitrant" , "Insolent" , "Not submissive to authority" .)