In 2016, during the pesidential contest between Hilary Clinton and Donald Trump, in which both candidates were caught making untrue statements, I characterized the difference between them as follows:
When Clinton tells untruths she knows what the truth is and is consciously saying something else — just like most of us when we lie.
Trump, on the other hand, “shoots from the hip” in any given situation, saying what he thinks will sound best in any given situation. Sometimes he contradicts himself multiple times in the space of just a few hours and seems to be wholly unaware of it.
Well, I just found out that a well-known philosopher, Harry Frankfurt, has written an entire book on the subject, and am feeling quite proud that my thoughts run along similar lines as a famous academic 
