Sounds as if the blooming thing is corny material (5)
I believe the answer is:
flour
'material' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for flour that I've seen before include "The stuff of bread" , "Fine-ground grain" , "Delivery from miller" , "White powder" , "Wheat meal" .)