Remove unruly brats in turn (8)
I believe the answer is:
abstract
'remove' is the definition.
(thesaurus)
'unruly brats in turn' is the wordplay.
'unruly' is an anagram indicator.
'in' indicates putting letters inside.
'turn' becomes 'act' (theatre**).
'brats' with letters rearranged gives 'bstra'.
'bstra' inserted inside 'act' is 'ABSTRACT'.
(Other definitions for abstract that I've seen before include "Brats act in non-concrete way" , "Remove - what isn't tangible" , "sculpture by Hepworth" , "Theoretical; abstruse" , "Take away - theoretical" .)