Plant sap (5)
I believe the answer is:
resin
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">plant sap</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that plant sap can be written as resin)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for resin that I've seen before include "varnish, perhaps" , "Cannabis, say" , "Myrrh, for instance" , "Viscous fluid from tree sap" , "Sticky stuff oozing from trees" .)