Bottom to thrash in confused situation (6)
I believe the answer is:
bedlam
'confused situation' is the definition.
(Bedlam can mean a state of chaos or madness)
'bottom to thrash' is the wordplay.
'bottom' becomes 'bed' (synonyms).
'to thrash' becomes 'lam' (both can mean to hit).
'bed'+'lam'='BEDLAM'
'in' is the link.
(Other definitions for bedlam that I've seen before include "Loud confused noise" , "Blamed for deafening noise" , "Blammed for uproar" , "Mayhem" , "State of extreme confusion and disorder" .)