Unauthenticated (10)
I believe the answer is:
apocryphal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unauthenticated</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for apocryphal that I've seen before include "Fabulous" , "probably made-up" .)