### Clue: Catalogues keeping subset back for radicals (9)
### Answer: LENINISTS 
 ### Explanation: Definition: radicals
 LISTS(complete … of items/catalogues) **containing**(keeping) **reversal of**(… back) NINE(9, the clue number in this crossword whose answer is "subset").
Defn: …/believers of the principles and theories of Marxist Vladimir Lenin.