Unserious
Etymology
The ordinary word unserious (not serious), narrowed online into a stronger charge of absurdity. It spread on Black Twitter and TikTok around 2021–2022, frequently as “this app is so unserious” or “he’s unserious.”
adjective · /un-SEER-ee-us/
Frivolous, absurd, or not to be taken seriously — often said with amused disbelief.
What it names
It names conduct or content so ridiculous it forfeits any claim to be treated as earnest — a verdict that something, or someone, is operating as a joke whether or not it means to. “This is so unserious” is both a dismissal and, often, admiration for the absurdity.
Example
The company’s official account replied to a complaint with a cat GIF — this brand is so unserious.
Related idea
Different from unhinged: unhinged is chaotic and unrestrained, while unserious simply can’t be believed as sincere — ridiculous rather than wild.