Watered down in barrels coming from lawbreakers (4)
I believe the answer is:
weak
'watered' is the definition.
(thesaurus)
'down in barrels coming from lawbreakers' is the wordplay.
'down' suggests deleting specific letters ('down' can mean missing).
'barrels' becomes 'wine barrels' (wine barrel is a kind of barrel).
'coming from lawbreakers' becomes 'ak' (I can't explain this - if you can you should give a lot more credence to this answer).
'wine' with 'in' taken away is 'we'.
'we'+'ak'='WEAK'
Can you help me to learn more?
(Other definitions for weak that I've seen before include "Puny" , "Wanting in physical strength" , "Lacking strength" , "Undefended" , "Feeble, powerless" .)