blue check

Meanings

1. A Twitter user whose account was verified by Twitter as authentic (i.e. not a parody or imposter account) and deemed to be of public interest prior to this system's replacement by a paid verification scheme in early 2023.
2. An online troll, provocateur, or grifter who uses a paid account to attract greater attention after the early 2023 change on Twitter.

Etymology

From the blue check mark badge that was previously displayed beside the names of such users. The second sense derives from the rude behavior from an influx of users who paid for extra features in their Twitter accounts from early 2023 onwards.