Indigestion (9)
(Other definitions for heartburn that I've seen before include "You'll get feeling of discomfort" , "Chest pain" , "Form of indigestion" , "Disorder" , "Hot sensation in lower chest from indigestion" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">indigestion</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that indigestion can be written as dyspepsia)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for dyspepsia that I've seen before include "Indigestion" , "It was enough to make any man sick" , "Stomach problem" , "internal upset" , "digestive complaint" .)