Both are used according to wiktionary: https://en.wiktionary.org/wiki/brain_rot https://en.wiktionary.org/wiki/brain_rot Also, OUP and others have picked a nu

Both are used according to wiktionary: https://en.wiktionary.org/wiki/brain_rot https://en.wiktionary.org/wiki/brain_rot Also, OUP and others have picked a number of words of the year having spaces: https://en.wikipedia.org/wiki/Word_of_the_year https://en.wikipedia.org/wiki/Word_of_the_year For example, "goblin mode" (2022). There are hundreds of words in the English language that contain spaces.