One threatened with it, may go into it (6)
I believe the answer is:
hiding
'it' is the definition.
The definition suggests a singular noun which matches the answer.
'one threatened with it may go' is the wordplay.
I cannot really see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
'go' could be 'din' (dinning is a kind of going) and 'din' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
'into' acts as a link.
Can you help me to learn more?
(Other definitions for hiding that I've seen before include "big defeat" , "going underground" , "Concealment - severe defeat" , "Concealing oneself - good thrashing" , "Beating; keeping out of sight" .)