Compact, firm (5)
I believe the answer is:
solid
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">compact</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">firm</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for solid that I've seen before include "continuous" , "Substantial - having three dimensions" , "Unbroken" , "from one getting pushed around" , "cone-shaped, say" .)