Poisonous fungus (9)
I believe the answer is:
toadstool
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">poisonous fungus</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for toadstool that I've seen before include "Something poisonous" , "Umbrella-shaped fungus" , "Support for little people" , "jack-o'-lantern?" , "Common fungus" .)