He lacks intellectual curiosity and sophistication. His malignant narcissism is so extreme that he possesses the cognitive dexterity and emotional intelligence of a PMSing 16-year old. He has no common sense. He has no actual acumen on any subject of consequence. He has no real understanding of actual policies as his intellect is limited entirely to what earns him adulation and praise.
That is why he can ramble on incoherently for several minutes talking about the size of Arnold Palmer’s cock or utter laughably ignorant drivel like “Who knew healthcare could be so complicated?” while claiming to impress medical experts on how much he understands novel viruses, or making breathtakingly stupid claims about knowing more about ISIS than the generals, or musing about 18th century aviation during the American Revolutionary War, or offering up bafflingly idiotic drivel about Frederick Douglass doing terrific things in the 21st century despite Douglass dying before the 1900s, or any of the other thousands upon thousands of head-scratching examples of Trump opening his fat ****ing mouth to demonstrate beyond a shadow of a doubt that his mental faculties rival that of an imbecile’s.
In short, yes, he is a ****ing idiot. That is not even debatable. The greater question is: What does it say about the intelligence of the people whom Trump makes sense to?