Cause; grounds (6)
I believe the answer is:
reason
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">cause</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">grounds</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for reason that I've seen before include "Sanity, the ability to think" , "Justification; sanity" , "Logic; excuse" , "Cause or motive" , "Employ logic" .)