Lacking organisation, band is infiltrated by US cops (8)
I believe the answer is:
slapdash
'lacking organisation band is infiltrated by us cops' is the definition.
I can't tell whether this definition defines the answer.
'band is infiltrated by us cops' is the wordplay.
'band' becomes 'sash' (a band of material).
'is infiltrated by' is an insertion indicator.
'us cops' becomes 'LAPD' (Los Angeles Police Department).
'sash' going around 'lapd' is 'SLAPDASH'.
Can you help me to learn more?
(Other definitions for slapdash that I've seen before include "Irresponsible" , "Messy" , "recklessly" , "Slipshod, sloppy" , "Blow followed by sprint - that's careless" .)