Donald Trump said that Senator John McCain is or was no hero. If one were to use a very narrow definition of the word, hero, Donnie could be correct. The narrow definition would be bravery perhaps a scoch more than the expected, in this case, in the military..
I suggest that if the narrow definition is used, it should be stated that the definition limits are both explained and are the only parameters. I guess being captured doesn't constitute bravery. However Donnie does not explain any parameters and the preponderance of scope of what a hero is, as stated in Merriam Webster, should be applied.
I am not a John McCain fan, but would call him a hero. For his service, he is almost universally admired, he has shown great courage in his prisoner ordeal. and while I may disagree with most of his politics, he is a man of many fine attributes.
So Donnie, grab yourself a dictionary, have someone read to you the definition of Hero, and apologize to the Senator.