untruthful russian

• нече́стный

  dishonest, deceitful, untruthful

  unfair, dishonourable, underhand

• вру́щий

  lying, untruthful, mendacious

• брехли́вый

  yappy, given to barking, barking constantly

  lying, mendacious, untruthful

• навра́вший

  having lied, untruthful

• лживо

  falsely, deceitfully, mendaciously, untruthfully