Brought up trick used to convert antisocial extremists active at night (9)
I believe the answer is:
nocturnal
'active at night' is the definition.
(I've seen this before)
'brought up trick used to convert antisocial extremists' is the wordplay.
I cannot quite see how this works, but
'convert' could be 'turn' (synonyms) and 'turn' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for nocturnal that I've seen before include "Relating to the night" , "Active after dark" , "going abroad furtively?" , "Like bats" , "Appertaining to the night" .)