Prevaricator (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">prevaricator</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for liar that I've seen before include "Phoney" , "man of fiction?" , "Storyteller" , "Bearer of false witness" , "Fibber" .)