Learn languages while watching YouTube & Bilibili
knockOut Study turns every subtitle into an interactive lesson. Tap any word for an instant dictionary lookup — without ever leaving the video.
Up and running in 30 seconds
No setup. No configuration. Just install and watch.
Install the extension
Add knockOut Study to Chrome in one click. No configuration needed.
Enable subtitles in the player
Turn on subtitles normally in YouTube or Bilibili. knockOut picks them up automatically.
Tap any word to look it up
The subtitle overlay appears over the video. Hover for a quick glance, click for the full dictionary card.
Everything you need to study smarter
Built for serious language learners who watch native content.
Tap any word
Click any word in the subtitle to get an instant dictionary lookup — translation, pronunciation, part of speech, and example sentences.
Hover preview
Hover over a word to see the top 3 translations instantly — without pausing or clicking.
Save words
Build your personal vocabulary list as you watch. Saved words sync to your knockOut account across all devices.
Phonetic mode
Enable ruby annotations to see pinyin above Chinese or romaji above Japanese — every word, every cue.
Fullscreen & cinema
Works in all YouTube and Bilibili layout modes. The overlay repositions itself when you switch — always centered by default.
Keyboard shortcuts
A / S / D to jump to the previous, repeat the current, or skip to the next subtitle line — without touching the mouse.
Start watching. Start learning.
A free knockOut account gives you full access to the extension. Sign up takes 30 seconds.
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