Concealing (6)
I believe the answer is:
hiding
'concealing' is the definition.
(I know that concealing can be written as hiding)
This is the entire clue.
(Other definitions for hiding that I've seen before include "physical punishment" , "Concealing oneself - good thrashing" , "Beating; severe defeat" , "Beating - state of concealment" , "Beating - retreat" .)