Using spicy root could be controversial (3,6)
I believe the answer is:
hot potato
'using' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'spicy root could be controversial' is the wordplay.
I cannot really understand how this works, but
'spicy' could be 'hot' (synonyms) and 'hot' is present in the answer.
The remaining letters 'potato' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for hot potato that I've seen before include "Difficult matter" , "Tricky problem" , "Top hat too (anag)" , "tricky issue?" , "Burning issue" .)