Imaginary thing (7)
I believe the answer is:
figment
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">imaginary thing</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 figment that I've seen before include "Deception, sham" , "Fantastic invention" , "fantastic idea" , "Fancy, fabrication" , "One's imagined" .)