Unproductive, bare (6)
I believe the answer is:
barren
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">unproductive</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">bare</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for barren that I've seen before include "Arid, infertile" , "Bleak, lifeless" , "Dull" , "Unproductive of life" , "Unable to bear young" .)