Synonyms for Untruthful:

adj.

crooked (adjective)
dishonest, unscrupulous, devious, unprincipled, dubious.
deceitful (adjective)
cunning, mendacious.
dishonest (adjective)
deceitful, untrue, crooked, lying, insincere.
faithless (adjective)
untrue.
false (adjective)
fake, specious, counterfactual, spurious.
lying (adjective)
wrong.
mendacious (adjective)
insincere, mendacious.
untruthful (adjective)
deceitful, lying, fraudulent, crooked, two-faced, scheming, devious, deceptive, false, corrupt.

n.

cunning, unscrupulous, corrupt, unprincipled, dubious. counterfactual, wrong, true, spurious, untrue, specious, Truthless, false. deceitful, honest. untrue (noun)
false, fraudulent, fake, unlikely.
untruthful (noun)
lying, dishonest, mendacious.

Other synonyms:

fraudulent, unprincipled, false, counterfactual, crooked, unscrupulous. deceitful, Truthless, cunning, untrue, dubious. specious. spurious, wrong. corrupt. Other relevant words:
deceitful, unprincipled, counterfactual, untrue, corrupt, false, insincere, spurious, dishonest, specious, fake, mendacious, crooked, cunning, wrong, Truthless, unscrupulous, fraudulent.

Usage examples for untruthful

  1. Through fear, that mother as a child had become untruthful and in later years had a bitter struggle with the temptation to sacrifice the truth to save herself any annoyance. – The Girl and Her Religion by Margaret Slattery
  2. She would rather follow him to the church- yard and lay him in his grave beneath the bending elms, than to have him untruthful or wicked. – Winning His Way by Charles Carleton Coffin
  3. I told her how to manage in going to her old employer, and to tell her you were deceived by that young man, but you found him untruthful – A Woman's Life-Work Labors and Experiences by Laura S. Haviland