Incurably nasty fellow? (3)
I believe the answer is:
cur
'nasty fellow?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'incurably' is the wordplay.
'CUR' is hidden within the letters.
However, I am unsure how this is indicated.
Can you help me to learn more?
(Other definitions for cur that I've seen before include "Mangy dog" , "Non-pedigree dog" , "Miserable dog" , "Base fellow" , "Aggressive dog" .)