Some Emacs functions and variables have “dwim” in their name somewhere. DWIM stands for “Do What I Mean”. Usually these functions try to do the right thing, depending on the context.

For example, consider the DiredMode variable dired-dwim-target. If non-nil, this lets Dired know that you’d like it to guess a default target for commands like copy and move. Say you have your Frame split into two Dired Windows; in this case, Dired will assume that you want to copy/move the file from the one into the other. This is cool stuff.

List of DWIM-like extensions

See WikiPedia:DWIM.