dishonest talk or behaviour
duplicity - deceit
Somebody who shows ‘duplicity’ is two-faced and engages in action or speech that is ended to deceive. Often this is done to hide one’s true feelings or intentions for personal gain at the expense of others. However, it does not always have negative connotations. For example, sometimes people can act in a duplicitous way simply to fit in better.
Brenda runs a very tight ship at that organization. She does not tolerate any lying or duplicity.
I pulled out of the deal because the other party were engaging in behaviour I thought to be duplicitous.
The con artist acted as if he were a high-powered salesperson, but I was never taken in by his duplicity.