mendacious [men-dey-shuh s]
adjective
1. telling lies, especially habitually; dishonest; lying; untruthful: a mendacious person.
2. false or untrue: a mendacious report.
Antonyms
1, 2. veracious.
Origin: 1610-20; < Latin mendāci- (see mendacity ) + -ous
Now YOU come up with a sentence (or fic? or graphic?) that best illustrates the word.