Mind-blowing means something hits you so hard — with excitement, shock, or strangeness — that it feels as if it knocks your thoughts over. A view, a film, a fact, or a show can be mind-blowing. It is informal and strong: you say it to friends, not in a careful school essay unless you want that punch. It comes from the saying that a thing “blows your mind.” People now stretch it to almost anything that amazes them, even a meal. Though actually, if something is only quite nice, the word is too big. It is looser and louder than “very good.”