Misleading rumour, hoax (6)
I believe the answer is:
canard
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">misleading rumour</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">hoax</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that canard is a type of hoax)</span><br/ ><br/ ></span>
(Other definitions for canard that I've seen before include "Ugly rumour" , "False rumour or story, from France" , "Deliberately misleading fabrication" , "A French kind of false rumour" , "False rumour, originally from France" .)