Impetuous person (7)
I believe the answer is:
hothead
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">impetuous person</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for hothead that I've seen before include "maniac" , "Excitable person" , "An impetuous person with warm cranium" , "Headstrong type" , "Madcap" .)