Wilful leaders of dangerous enterprise get set free (10)
I believe the answer is:
deliberate
'wilful' is the definition.
(synonyms)
'leaders of dangerous enterprise get set free' is the wordplay.
'leaders of' suggests taking the first letters.
'get' is a charade indicator (letters next to each other).
'set free' becomes 'liberate' (synonyms).
The first letters of 'dangerous enterprise' is 'de'.
'de'+'liberate'='DELIBERATE'
(Other definitions for deliberate that I've seen before include "Intentional; think carefully" , "Consider carefully" , "Well considered" , "Planned" , "muse" .)