Ticker (5)
I believe the answer is:
heart
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ticker</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for heart that I've seen before include "Feeling" , "It's in the chest" , "Earth (anag) -- compassion" , "Cardiac organ" , "Vital part" .)