mendacious (men-DAY-shuhs) adjective
Telling lies, especially as a habit.
[From Latin mendac-, stem of mendax (lying), from mendum (fault or defect) that also gave us amend, emend, and mendicant.]
Today's word in Visual Thesaurus.
"Forget Disney's cartoon tale of the mendacious marionette whose doweled nose grows longer with every fib."
-- Roger McBain; Ballet Helps 'Pinocchio' Step Out In New Direction; Evansville Courier & Press (Indiana); May 11, 2005.