Pop-Up Dictionary on selected word. You can use dictionary sites which provide better and more detailed definitions than e.g. google translate.

Pop-Up Dictionary Firefox Add-On
Pop-Up Dictionary is a Firefox add-on that allows you to translate selected words on-the-fly using online dictionary sites. It supports multiple dictionaries and even allows you to define your own custom dictionary sites. The add-on logs the dictionary chosen for each web page you visit, making future translations seamless.
Add-on stats
Manifest V2
Weekly download count: 2
Firefox on Android: Yes
Permissions:
- storage
Size: 25.85K
URLs: Website ,Privacy policy
Full description: See detailed description
Ranking
Other platforms
Not available on Chrome
Not available on Android
Not available on Edge
User reviews
It works, but on every page I visit, it says that a script is blocking the direct opening, it shows "open PUD", and only when clicking it, it opens up the popup with the definition. So, no problem, it works, but there's probably something that bugs a little, as there's this warning message.
The brilliant point is that we can add custom dictionaries!
by PERCE-NEIGE, 2020-12-05
If you find a way to make it work without the need to watch a SILENT how-to video, I'll come back to try it. In the meantime, I'll find an alternative.
by BoilingOil, 2020-04-15
Works somewhat. I added google translate and had to set it to open in a new tab, otherwise it wouldn't work (a green prompt). As of now I can double tap a word and it will open in google translate, but the annoying prompt is still there.
I use Android.
To conclude, three stars.
by Jan, 2020-03-28
Add-on safety
Risk impact
Pop-Up Dictionary requires a few sensitive permissions. Exercise caution before installing.
Risk impact analysis details
- Critical Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- High ******* ******* **** *** ****** ***** *** ***** ** ******* **** ********* ********* ** * *********** *****
- Low ******* ****** ** *** ********* ********
Risk likelihood
Pop-Up Dictionary has earned a fairly good reputation and likely can be trusted.
Risk likelihood analysis details
- High This extension has low user count. Unpopular extensions may not be stable or safe.
- Low **** ********* *** ******* **** **** * ****** **** ***** ******** *** **** ****** ** ** ****** *** *****
- Low **** ********* *** ***** **** **** * ****** **** ***** ********** *** **** ****** ** ** ****** *** *****
- Good **** ********* *** **** **** *******
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