I accidentally added an incorrectly spelt word to the macOS spelling dictionary via an Add to Dictionary menu item. Surprisingly, there was no inverse “remove from dictionary” option to undo this! Additionally, I realized there is no System Preferences page to to edit the custom dictionary. There are two ways to fix this with macOS (but none for iOS).

Solution 1: Unlearn Spelling in TextEdit

If you can still remember the misspelt word:

  1. Copy or type the word into TextEdit,
  2. Right-click and select Unlearn Spelling,
  3. Quit - no need to save.

TextEdit to Unlearn Spelling

Solution 2: Removing words by editing LocalDictionary

Simply edit the plain text file that stores all custom words. I do this via the Terminal:

  1. Edit the LocalDictionary file in ~/Library/Spelling/LocalDictionary using your text editor of choice,
  2. Delete incorrect lines,
  3. Save.
vi ~/Library/Spelling/LocalDictionary
~$ vi ~/Library/Spelling/LocalDictionary