Rex Tillerson came a little bit closer Thursday to saying what he actually thinks of President Donald Trump.

The fired secretary of state, who while in office reportedly called Trump a "moron" (and declined to deny it), expounded on his thoughts on the president in a rare interview with CBS News's Bob Schieffer in Houston.

It wasn't difficult to read between the lines. Tillerson said Trump is "pretty undisciplined," "doesn't like to read," and repeatedly attempted to do illegal things. He didn't call Trump a "moron," but he didn't exactly suggest Trump was a scholar ­— or even just a steady leader.

"What was challenging for me coming from the disciplined, highly process-oriented Exxon Mobil corporation," Tillerson said, was "to go to work for a man who is pretty undisciplined, doesn't like to read, doesn't read briefing reports, doesn't like to get into the details of a lot of things, but rather just kind of says, 'This is what I believe.' "

Tillerson said Trump believes he is acting on his instincts rather than relying on facts. But Tillerson seemed to suggest that it resulted in impulsiveness.

"He acts on his instincts; in some respects, that looks like impulsiveness," Tillerson said. "But it's not his intent to act on impulse. I think he really is trying to act on his instincts."

Perhaps the most damning quote came when Tillerson talked about how Trump as president regularly attempted to do things that violated the law.

"So often, the president would say, 'Here's what I want to do, and here's how I want to do it,' " Tillerson said, according to the Houston Chronicle, "and I would have to say to him, 'Mr. President, I understand what you want to do, but you can't do it that way. It violates the law.' "

Tillerson also appeared to take a shot at Trump's chief method of communication, Twitter.

"I will be honest with you: It troubles me that the American people seem to want to know so little about issues — that they are satisfied with a 128 characters," Tillerson said.

He was quick to say that that wasn't meant as a shot at Trump, but our political system more broadly.