a liar
Examples
A liar ought to have a good memory.
The only thing worse than a liar is a liar that's also a hypocrite!
I talk about the gods, I am an atheist. But I am an artist too, and therefore a liar. Distrust everything I say. I am telling the truth.
A miser and a liar bargain quickly.
The punishment of a liar is that he is never believed, even when he speaks the truth.
A liar should have a good memory.