Fool; artery problem (4)
I believe the answer is:
clot
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">fool</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">artery problem</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for clot that I've seen before include "Coagulate - fool" , "3 [DUMMY]" , "A lump in a blood vessel" , "Clumsy person" , "Curdle - idiot" .)