Some people just want to cycle through their lessons like flash cards before the lesson quiz. Unfortunately, the meaning of the lessons below the kanji/vocab can ruin that experience.
This should help.

(apart from this lesson, you never have to worry about spoilers in your lessons any more)
How to use
- do lessons. All of them. Yesterday!
Features (v4.0)
- It does at it says on the box (hides the meaning of kanji/vocab in lessons for those who like to cycle through them like flash-cards)
- Hover over the lesson item to make the meaning visible again
- Automatically shows meaning if you get to the meaning tab for added clarity and for those who ignore za almighty mnemonics (say that three times really fast with a german accent to get a free virtual cookie)
How to install
- Make sure you have the Greasemonkey (Firefox) or Tampermonkey (other browsers) add-on installed, so you can enjoy user scripts.
- Go to https://greasyfork.org/en/scripts/23485-wanikani-lesson-spoiler-removal
- Click the green button (if that doesn’t work out, look at the guide linked below)
- BOOM, DONE!
How to install/edit user scripts guide:
/t/Visual-Guide-on-How-To-Install-A-Userscript/12136/1
Change log:
v4.0
- Fix for flickering bug (by shikaji)
v3.0
- Shows meaning when navigated to meaning tab by arrow keys, shortcut keys, or clicking
v2.1
- Hover effect added to undo any disappearing magicz
v2.0
- Works on Firefox too
v1.0
- initial release
Note: working on Firefox and Chrome (technically any browser)
Anyone know if there’s anything similar to this somewhere that works for firefox? Also, an option to turn it on and off would be nice. Good idea for the script though!