Growing up, I came to believe that the word "concerted" means something like "effortful" or "work hard to do something". I later learned that it actually refers to a group of people working together (in concert) to accomplish something [1]. So technically, a person cannot make a concerted effort to do something alone.
Seeing the word used here in this technically incorrect way leads me to wonder how uncommon my experience is. Are we on our way to redefining this word with a more relaxed definition?