What GB said. "Toxic narcissist" is a perfect phrase.
Trump has no sense of humor (unless he's laughing at his own jokes,) he is unable or unwilling to admit he's ever wrong about anything, and he has zero intellectual curiosity or desire to learn anything, because he thinks he already knows it all. To emotionally stunted people like him, the entire universe revolves around themselves and they become angry, defensive and abusive when other people don't understand that "fact." Notice how he is using the office of president to take revenge on all the people he thinks were mean to him - for instance, trying to erase Obama's legacy because Obama told a joke about him at the WH Correspondence Dinner a few years back.
History is not going to look back kindly on the US for foisting this mentally unstable, tin-pot-dictator-wannabe on the globe.