What it means
Terminally online describes someone so glued to the internet that their whole worldview is warped by it, taking niche online drama deadly seriously and assuming everyone offline gets their references. They argue about discourse no normal person has heard of and forget how real conversations work. It's a step beyond chronically online, basically past the point of no return.
Usage examples
"He brought up some obscure Twitter feud at dinner, absolutely terminally online."
"Only a terminally online person would expect their gran to know what that meme means."
"She's so terminally online she thinks a three-day TikTok scandal is a real-world emergency."
"Bro said touch grass is ableist and then live-posted the group chat fallout. Properly terminally online."
Where it comes from
It builds on chronically online, swapping chronic for terminal to mark a condition seen as basically incurable. The joke is that touching grass is no longer an option.
Other ways to say it
This expression also appears in