As adjectives the difference between mendacious and truthful
is that mendacious is lying, untruthful or dishonest while truthful is honest, and always telling the truth.
mendacious
English
Adjective
(
en adjective)
(of a person) Lying, untruthful or dishonest.
(of a statement etc) False or untrue.
truthful
English
Adjective
(
en adjective)
Honest, and always telling the truth.
Accurately depicting what is real.
Antonyms
* untruthful