Bad actor in shambles (3)
I believe the answer is:
ham
'bad actor' is the definition.
(a ham is someone who overacts)
'in shambles' is the wordplay.
'in' says the answer is hidden in the clue.
'HAM' can be found hidden inside 'shambles'.
(Other definitions for ham that I've seen before include "Overacting actor" , "Cured pig's meat" , "Bad actor; Noah son" , "Meat from a pig" , "Meat of the hog" .)