Covering up thrashing (6)
I believe the answer is:
hiding
I believe this clue is a double definition.
'covering up' is the first definition.
(I've seen this before)
'thrashing' is the second definition.
(I've seen this before)
(Other definitions for hiding that I've seen before include "big defeat" , "Hushing up" , "Concealing oneself - good thrashing" , "Thrashing; lying low" , "Keeping secret" .)