Let's say I want all words "bad" be red (#ff0000).
What should I add to init.el so the color of the string/word "bad" will turn red in all modes whether it is org mode or some other mode into this:
https://i.imgur.com/7WMwG1s.png
I would like to do it in every file I have open and if possible it should be real time without any manual evaluation etc.
Is it possible to achieve in Emacs without installing any plugin?