Non-fire treated as a fire (7)
I believe the answer is:
inferno
'a fire' is the definition.
(I know that inferno is a type of fire)
'non-fire treated' is the wordplay.
'treated' is an anagram indicator.
'non'+'fire'='nonfire'
'nonfire' anagrammed gives 'INFERNO'.
'as' acts as a link.
(Other definitions for inferno that I've seen before include "Fierce fire" , "hot spot" , "blazer?" , "Nine Circles here" , "Hellish conflagration" .)