Polish gang set up attractive lure for victims (9)
I believe the answer is:
honeytrap
'attractive lure for victims' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'polish gang set up' is the wordplay.
'polish' becomes 'hone' (I've seen this in another clue).
'gang set' becomes 'party' (I can't justify this - if you can you should give a lot more credence to this answer).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'party' in reverse letter order is 'ytrap'.
'hone'+'ytrap'='HONEYTRAP'
Can you help me to learn more?
(Other definitions for honeytrap that I've seen before include "Plot using sexual wiles to lure someone into indiscretion" , "questionable spying technique" , "Planted lovely" , "snare" , "seductive scheme" .)