Committing perjury
I believe the answer is:
lying
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">committing perjury</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for lying that I've seen before include "Dishonest" , "not to be trusted?" , "Flat" , "possibly, to be mendacious" , "Invention" .)