One uses strange material for debate (5)
I believe the answer is:
issue
'material for debate' is the definition.
'one uses strange' is the wordplay.
'one' becomes 'i' (Roman numeral).
'strange' indicates anagramming the letters.
'uses' anagrammed gives 'ssue'.
'i'+'ssue'='ISSUE'
(Other definitions for issue that I've seen before include "Matter of contention" , "One of a series published periodically" , "Send out or distribute for use" , "Offspring or edition" , "Question - outgoing - children" .)