Sound in mind (4)
I believe the answer is:
sane
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sound in mind</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sane that I've seen before include "Identical" , "Free from mental disorder" , "Compos mentis" , "In full possession of mental faculties" , "Rational" .)