既読スルー

• Reading: きどくスルー
• Romaji: kidoku surū
• Kanji breakdown: 既 (ki, already) + 読 (doku, read) → already read; スルー (surū, from English 'through') → letting it pass / ignoring
• Pronunciation: /ki.do.ku.su.rū/

Meaning

Being left on read — when someone reads your message (shown by the read receipt) but deliberately does not reply.

A compound of 既読 (kidoku, 'already read' — the read receipt indicator on LINE) and スルー (surū, from English 'through,' meaning to let something pass). 既読スルー became a major social phenomenon in Japan after LINE introduced read receipts. The anxiety of seeing 既読 without receiving a reply spawned widespread discussion about messaging etiquette. It is considered ruder than simply not seeing a message, because the sender knows the other person read it and chose not to respond.

Examples

1. また既読スルーされた。何か悪いこと言ったかな。 I got left on read again. Did I say something wrong?
2. 既読スルーされると地味にへこむよね。 Getting left on read is kind of a bummer, isn't it?
3. 忙しいだけかもしれないけど既読スルーは気になる。 They might just be busy, but being left on read still bothers me.

Usage Guide

Context: LINE, messaging, casual conversation

Tone: frustrated, anxious

Do Say

• 既読スルーされてへこんでる。 (I'm down because I got left on read.)
• 既読スルーするつもりなかったけど返信忘れてた。 (I didn't mean to leave you on read, I just forgot to reply.)

Don't Say

• 既読スルーを問い詰める (Don't confront someone aggressively about leaving you on read — they might have been busy)

Common Mistakes

• Assuming 既読スルー is always intentional — people genuinely forget to reply after reading messages
• Not knowing that 既読スルー is specific to platforms with read receipts, especially LINE

Origin & History

Compound of 既読 (kidoku, 'already read,' from LINE's read receipt feature launched in 2011) and スルー (surū, from English 'through,' meaning to ignore/let pass). The term became widely used from 2012 onward as LINE became Japan's dominant messaging app.

Cultural Context

Era: 2012 onward, after LINE's read receipt feature

Generation: All LINE users

Social background: Universal in Japan

Regional notes: Used across Japan. LINE is the dominant messaging app with over 90 million users. 既読スルー anxiety is a widely discussed social phenomenon.