Lying facedown (5)
I believe the answer is:
prone
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lying facedown</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for prone that I've seen before include "Recumbent, likely" , "Lying face downward" , "Placed face down" , "Liable (to suffer) - lying down" , "Lying face down - inclined" .)