Solid (5-11)
There are a few possibilities for this:
three-dimensional
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">solid</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that solid can be written as firm)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for firm that I've seen before include "Unyielding business concern?" , "Steady sort of business organisation" , "Unyielding; company" , "Company - solid" , "Organization" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">solid</span>' is the definition.<br/ ><span class="explanation-format__explanation">(associated in meaning)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for hard that I've seen before include "Difficult; rigid" , "Solid; tough" , "Firm; demanding; stern" , "to be listened to in Scotland" , "Unyielding" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">solid</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for three-dimensional that I've seen before include "Having length, breadth and width" , "Lifelike, real" .)