crossing the line; going too far
Internet slang for overstepping a boundary, similar to 一線を越える. Used when someone's words or actions become inappropriate or excessive.
See also: 一線を越える
I think that comment crossed the line.
Even as a joke, going too far is not acceptable.
Standard kanji spelling using 越え.
Variant spelling using 超え; both are used, but 越え is more common.
Compound of ライン (line) and 越え (crossing), modeled on the phrase 一線を越える. The exact origin is uncertain, but it likely emerged in online communities.