Common infection (4)
I believe the answer is:
cold
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">common infection</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for cold that I've seen before include "Lacking emotion" , "Lacking warmth" , "Frigid" , "Unfriendly" , "Dead" .)