Very clever person
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">very clever person</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for brainbox that I've seen before include "Skull - clever clogs" , "Mastermind" , "Clever type" , "Very clever figure" , "quiz champion?" .)