untruthful vs mendacious

untruthful and mendacious both are adjectives.

Word	Noun	Adjective	Verb	Adverb
untruthful	No	Yes	No	No
mendacious	No	Yes	No	No

untruthful (adjective)	mendacious (adjective)
not expressing or given to expressing the truth	intentionally untrue
	given to lying