Stimulant (8)
I believe the answer is:
caffeine
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">stimulant</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 caffeine that I've seen before include "The drug in coffee" , "Fine face (anag.)" , "Stimulating alkaloid" , "it may produce a buzz" , "Compound in coffee" .)