Forest (4)
I believe the answer is:
wood
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">forest</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for wood that I've seen before include "Cooing bird" , "Grove" , "Old conductor" , "Dense growth of trees" , "Driver, perhaps" .)