Group, ill-willed at the outset, attempt robbery and violence (8)
I believe the answer is:
banditry
'robbery and violence' is the definition.
(what bandits do)
'group ill-willed at the outset attempt' is the wordplay.
I cannot really understand how this works, but
'group' could be 'band' (band can mean a group of people) and 'band' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found within 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 banditry that I've seen before include "Plundering in gangs" , "Outlawry" , "Criminal behaviour" , "Activity of violent robbers" , "robbery" .)