If it is said about someone that he or she plays 4D chess, it is meant that the person behaves irrationally, incompetently and partly self-damagingly. The person displays behavior that is no longer comprehensible or explainable to others. The statement that someone plays 4D chess is used here to make fun of the person.
In another connotation, „playing 4D chess“ means that someone makes complicated and thought-out decisions that are simply not comprehensible to outsiders. In a positive sense, someone in 4D Chess is acting unorthodoxly, unusually, and very idiosyncratically. (However, the opposite is usually true. Someone thinks they are making good and rational decisions, but acts irrationally and incompetently).
What does (playing) 4D chess mean? Meaning, definition, explanation
Chess is a game in which thinking ahead is an essential part. You think about your moves and try to anticipate what moves your opponent will play and how he / she will react. Based on these assumptions you create your own strategy and adapt it.
In „4D Chess“ it now happens that for others it is no longer recognizable and transparent why someone makes certain decisions, what he or she intends to do with them and what goals this behavior serves.
About 2D, 3D and 4D Chess
Chess is a 2D game. It is played on a board with two axes. You can move a piece left, right, forward and backward.
3D is a variant of chess where you play on several horizontally stacked boards. There are three axes. Here you can move a piece to the left, right, forward, backward, as well as up and down.
3D chess is a much more complicated variant of normal chess. It is assumed that only majority of people with high intelligence can (and want to) play this game.
In 4D chess, the time component should be added. 4D-chess does not exist as a real game, but a 4D-chess could consist of several 3D-chess games. How this would look physically, however, is not known to the editors.
Since 3D Chess is already a game for the very intelligent, 3D Chess is a game for those whose intelligence is extremely high.
Further meaning of 4D Chess
In the US English colloquial language it is said that politicians or conspiracy theorists play 4D Chess when they make incomprehensible decisions. Here, 4D chess means that some decisions seem incompetent and wrong to outsiders, but actually serve a grand secret plan and are therefore ingenious.