Lookuber – YouTube Subtitles & Web Dictionary Firefox

Lookuber – YouTube Subtitles & Web Dictionary

By: Weiwei Add-on
Click any word in YouTube subtitles—or on any web page—to look it up across multiple dictionaries, hear it spoken, and save it to your own vocabulary book.

Features & Capabilities

Lookuber turns subtitles and web text into instant, clickable dictionary lookups.

On YouTube, Lookuber overlays clickable subtitles on top of the video. Turn on captions, click any word, and a dictionary card appears—definitions, phonetics, pronunciation audio, and translation into your chosen language. On any other web page, just select text to look it up the same way.

Never miss a word Unlike tools that show only the current line, Lookuber keeps previous subtitle lines on screen, so you can go back and look up something you just heard. And the moment you move your cursor onto a subtitle, the video pauses automatically—take all the time you need to read, click, and study, then it resumes the instant you move away. No frantic pausing, no rewinding, no missing the next line.

Features

  • 🎬 Clickable YouTube subtitles — full sentences split by punctuation, with word-by-word karaoke highlighting.
  • ⏸️ Hover-to-pause — moving onto a subtitle pauses the video automatically and resumes when you leave, so you never miss what comes next.
  • 🕘 Subtitle history — previous lines stay on screen so you can look back instead of losing them.
  • 🌐 Select-to-look-up on any page — trigger by hover, click, or a hotkey.
  • 📚 Multiple dictionaries — Google, Cambridge, Wiktionary, Bing, Jisho, Moedict and more, chosen automatically by your target language.
  • 🔊 Pronunciation audio where available.
  • 📒 Personal vocabulary book — save words with their sentence and video timestamp; export and import as JSON.
  • 🌍 11 interface languages, with an independently selectable translation target (30+ languages).
  • 🔒 Privacy-friendly — no data is collected by the developer. Lookups go only to the dictionary you choose.
No account, no sign-up. Just install and start clicking.

User Growth & Download Statistics

Manifest V3 Add-on
By:
Weiwei
Daily users:
1
Rating:
5.00
(1)
Version:
1.0.0 Last updated: 2026-06-20
Version code:
6311454
Creation date:
2026-06-17
Risk:
Very high risk impact High risk likelihood
Permissions:
Host permissions:
  • *://*.youtube.com/*
  • https://api.dictionaryapi.dev/*
  • https://translate.googleapis.com/*
  • https://dictionary.cambridge.org/*
  • https://cn.bing.com/*
  • https://jisho.org/*
  • https://www.moedict.tw/*
  • https://freedictionaryapi.com/*
Content scripts matches:
  • www.youtube.com
  • <all_urls>
Size:
2.88MB
URLs:
Website ,Privacy policy
Full description:
See detailed description
Source:
Firefox Add-ons Store
Data ingested on:
2026-07-24
Compare stats and ranking:

Contact the developer

Chrome-Stats does not own this Firefox add-on. Please use these information below to contact the Firefox add-on developer.
Developed by:
Weiwei
Firefox Add-ons Store
https://addons.mozilla.org/firefox/addon/lookuber/
Website:
https://docs.google.com/forms/d/e/1FAIpQLSczkzthWGAoMpP4YJWcs2kov4st8IYRdRySuEKmRnjadIHAuA/viewform

User Reviews

Loved it!
by ww*****, 2026-06-25
View all user reviews ›

Is Lookuber – YouTube Subtitles & Web Dictionary Safe?

Risk impact
Risk impact measures the level of extra permissions an extension has access to. A low risk impact extension cannot do much harms, whereas a high risk impact extension can do a lot of damage like stealing your password, bypassing your security settings, and accessing your personal data. High risk impact extensions are not necessarily malicious. However, if they do turn malicious, they can be very harmful.

Lookuber – YouTube Subtitles & Web Dictionary requires a lot of sensitive permissions. Exercise caution before installing.

Risk impact analysis details
  • Critical Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
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Risk likelihood
Risk likelihood measures the probability that a Firefox add-on may turn malicious. This is determined by the publisher and the Firefox add-on reputation on Firefox Add-ons Store, the amount of time the Firefox add-on has been around, and other signals about the Firefox add-on. Our algorithms are not perfect, and are subject to change as we discover new ways to detect malicious extensions. We recommend that you always exercise caution when installing a Firefox add-on.

Lookuber – YouTube Subtitles & Web Dictionary is recently added, and hasn't been around long enough for us to gather enough data to accurately assess its risk level.

Risk likelihood analysis details
  • High This extension has low user count. Unpopular extensions may not be stable or safe.
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