Clot, congeal (9)
I believe the answer is:
coagulate
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">clot</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">congeal</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for coagulate that I've seen before include "Set" , "Congeal" , "Cause to clot" , "(Of blood) solidify" , "Change from liquid into semi-solid as in catalogue" .)