Hasty article written about severe defeat (9)
I believe the answer is:
'severe defeat' is the definition.
'thrashing' can be an answer for 'defeat' (thrashing is a kind of defeat). I'm unsure of the 'severe' bit.
'hasty article written about' is the wordplay.
'hasty' becomes 'rash' (I've seen this in another clue).
'article' becomes 'thing' (both can mean an object).
'written about' means one lot of letters goes inside another.
'rash' put within 'thing' is 'THRASHING'.
Can you help me to learn more?
(Other definitions for thrashing that I've seen before include "A very heady defeat" , "punishment" , "Hiding" , "beating" .)