Keep hidden (7)
I believe the answer is:
conceal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">keep hidden</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for conceal that I've seen before include "Screen" , "hush up!" , "Hide, cover" , "Keep out of sight" , "'Hide, keep secret (7)'" .)