Heart; watch (6)
I believe the answer is:
ticker
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">heart</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(informal term for the heart)</span><br/ ><br/ >'<span class="explanation-format__original">watch</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for ticker that I've seen before include "Hunter, perhaps" , "timer" , "Heart (sl.)" , "Maybe watch" , "Telegraph instrument" .)