Not to say it's compulsive. Or neurotic. Or that he doesn't understand the difference between falsehood and reality. Or even that he confuses "the truth" with "what makes me look good."
He just lies. That's simple enough. It's in the court records. It's in his testimony. He lies to avoid financial loss but, more importantly, he lies to protect his reputation and his ego.
And this is not just "he's a politician [which he claims not to be] so he fudges the truth." He just plain, out and out lies, and in such a way and quantity that makes him clearly unsuited to be president.
Now I wish he'd get in trouble for lying under oath, like normal people do.
+John Bump Well, it's cost him a fair amount of money, from the law suits he's lost, but it hasn't discouraged him it seems.
Here's another detailed litany. https://www.washingtonpost.com/graphics/politics/2016-election/trump-lies/
Yeah, but when normal people lie under oath they end up in prison, not just paying fines (that he can, alas, easily afford.)