What is Another word for untruthful?

Here are some synonyms for "untruthful", depending on the context you need:

General:

* Dishonest

* Deceitful

* Lying

* False

* Fabricating

* Misleading

* Inaccurate

* Untrue

More formal:

* Mendacious

* Prevaricating

* Duplicitous

* Perfidious

Informal:

* Lying through your teeth

* Pulling someone's leg

The best word to use will depend on the specific situation and the tone you want to convey.