Least, slightest (7)
I believe the answer is:
minimal
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">least</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">slightest</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ ></span>
(Other definitions for minimal that I've seen before include "Least possible; negligible" , "Of a smallest amount" , "Very little" , "barely worth considering" , "Token" .)