This is one of those extensions you can't believe is not integrated into Firefox automatically.

It's fantastic, does exactly what it's supposed to do, and displays the text in a clear, easy to read font (not teeny tiny text) which is important for those of us on High Resolution monitors.

Thank you dev!

Excellent, lightweight and fast. Wish every add-on or better said every software was like that.
One problem though. I can't copy from the pop up text. Please make it possible. Really needed for note taking.

Update: I found the other one "Right Click Wiktionary" by you and it was possible to copy the text from it.

FF v.99

A terrific extension... using it multiple times every day... would be lost without it... Thank you!

Awesome addon. I have to login to rate for you :))

Very clean

UPDATED.

It turns out that you have to add the [W] button to the Bookmarks Toolbar to get this Extension to work. (at least, as of 01-DEC-2021)

Now things are working fine.

ADDENDUM:
Actually, things are working fine as long as the Icon is visible in the Firefox window/toolbar. If I move the button/icon over to the end of the row, we go back to "nothing shows up" status. If I shrink the window so the 'W' icon is no longer visible, we go back to "nothing shows up" status.

If I don't want the definition pop-up in the middle of the window, tough.