Preserve (a body) (6)
I believe the answer is:
embalm
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">preserve a body</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for embalm that I've seen before include "Treat corpse so as to retard decay" , "Preserve body, mummify" , "Prepare for burial" , "Use chemicals to preserve a dead body from decay" , "Prepare corpse for preservation (6)" .)