You might be wondering why you’d want to turn off spellcheck for a specific document in the first place. Microsoft Word, unsurprisingly, has a way to do this. If you want to hide spelling and grammar errors in a specific Word document without all of your other documents being affected by the setting change, then you’re in luck. Should be an option to turn off grammar/spell-checking for your document.
How to Hide Spelling and Grammar Errors in a Specific Word, File > Options > Proofing.
If you've turned off the automatic spelling and/or grammar checks, you can still go to the Review tab and click the Spelling & Grammar command to run a new check. Word 2016: Checking Spelling and Grammar, If you want to hide spelling and grammar errors in a specific Word document without all of your other documents being affected by the setting For example, if you don't want Word to mark spelling errors, grammar errors, or frequently confused words automatically, simply uncheck the desired option.
