Odour, scent (5)
I believe the answer is:
smell
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">odour</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that odour can be written as smell)</span><br/ ><br/ >'<span class="explanation-format__original">scent</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that scent is a kind of smell)</span><br/ ><br/ ></span>
(Other definitions for smell that I've seen before include "Nasal sense" , "Sniff" , "Scent" , "Hum" , "Unpleasant odour" .)