Nicotine plant (7)
I believe the answer is:
tobacco
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">nicotine plant</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 tobacco that I've seen before include "make a cot cob from this plant" , "Controversial plant grown commercially" , "Leaves to smoke" , "Smokable plant" , "Smoked narcotic plant" .)