Soundness of mind (6)
I believe the answer is:
sanity
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">soundness of mind</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sanity that I've seen before include "Sound sense" , "Rationality" , "Mental wellness" , "Reason, condition of being compos mentis" , "Soundness of mind" .)