According to Oxford University Press, which publishes the Oxford English Dictionary (OED), the term “brain rot” is defined as the “supposed deterioration of a person’s mental or intellectual state” as it relates to overdosing on online content without much of a narrative — like TikTok videos.
https://techcrunch.com/2024/12/02/brain-rot-wins-as-oxfords-word-of-the-year/