Area chief stopping New York's state of lawlessness (7)
I believe the answer is:
anarchy
'state of lawlessness' is the definition.
(I've seen this in another clue)
'area chief stopping new york's' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'chief' becomes 'arch' (synonyms).
'stopping' is an insertion indicator (inserted letters stop or plug a gap).
'new york' becomes 'ny'.
'arch' inserted within 'ny' is 'narchy'.
'a'+'narchy'='ANARCHY'
(Other definitions for anarchy that I've seen before include "State of civil disorder" , "State of disorder in society" , "Utter lawlessness" , "Absence of government" , "Society without government or law, chaos" .)