Mendacity
Definition: a lie or untruth
A “mendacity” can be a single thing someone says, or it can be a quality they possess.
Why I Looked It Up
From The Constitution of Knowledge: A Defense of Truth:
Even accounting for whatever you believe to be the biases of fact checkers, they was no serious disputing that the volume and audacity of Trump’s mendacity had broken through America’s epistemic guardrails, such as they were.
Update
Added on
From an H.P. Lovecraft short story:
[…] genuine photographs – actual optical links with what they portrayed, and the product of an impersonal transmitting process with prejudice, fallibility, or mendacity.
Basically, photographs (in that era) don’t lie.
Update
Added on
In a ruling over a case of prosecutorial misconduct, the judge said:
McAfee ruled that either Wade or Willis would have to leave the case, as an “odor of mendacity remains” over the circumstances of their relationship.