How to Unlearn Misspellings
If you’re in Pages, TextEdit, Nisus Writer Pro, BBEdit, or the like, you can Control-click the word, which will no longer have that red underline, and choose Unlearn Spelling to reverse your action. But if you’re in Safari, Google Chrome, or any other app that supports spell checking without implementing it fully, no Unlearn Spelling command is available.
The clumsy solution is to copy the offending word, paste it into TextEdit or a similar app, Control-click it there, and choose Unlearn Spelling from the pop-up menu. Effective, but awkward, particularly if you’ve ended up with a number of misspelled words in your dictionary over the years.
Here’s an alternative solution — you can edit your list of learned words directly, since it’s just a text file.