An impetuous one with fevered brow? (7)
I believe the answer is:
hothead
'an impetuous one with fevered brow?' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
This is the entire clue.
Can you help me to learn more?
(Other definitions for hothead that I've seen before include "maniac" , "An impetuous person with warm cranium" , "Harry Percy was one" , "Headstrong type" , "Person liable to get reckless impulses" .)