He is an ignorant, foolish, undereducated person who does not care to learn detail of things and believes himself an expert in things on the shallowest read possible — he doesn't like to be called stupid so he will believe anyone who seems authoritative, hence Peter Navarro/Ron Vara.

But he is a truly world-class bully.

He knows how it works, he was schooled in how it works (by Roy Cohn, who represented all five Cosa Nostra crime families at one time or another) because he had to deal with the legit mafia (concrete etc.) in New York in the 1970s. He perceives himself to be like a mafia don.

Josh Marshall of talkingpointsmemo once coined the term "dignity wraith" for what happens to people in Trump's orbit; the process of breaking them etc.

Only one person can make Trump himself lose dignity: Putin.