Psychoactive (14)
I believe the answer is:
hallucinogenic
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">psychoactive</span>' is the definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for hallucinogenic that I've seen before include "Causing unreal perceptions" , "leading to false perceptions" , "Some mushrooms are" , "Causing mental visions" .)