Microsoft Word allows you to add custom dictionaries and use them for spell checking. When you run a spell checker manually, or when it happens automatically as you type, Word compares the words in your document with the words in the main dictionary and any added custom dictionaries.
There are times when you want Word to use only words from the main dictionary to check spelling in a document. Custom dictionaries, for example, may contain special terms that are not recommended for use in the current document. You can set Word to use only the primary dictionary when doing spell checking and ignore any custom dictionaries.
Note: The illustrations for this article are from Word 2013.
To force Word to use only the primary dictionary, open an existing or create a new document and click the File (Queue).
In the menu on the left, click Parameters (Options).
On the left side of the dialog box Word options (Word Options) click on Spelling (Proofing).
In the parameter group When correcting spelling in Microsoft Office programs (When correcting spelling in Microsoft Office programs) check the box next to Suggest only from the main vocabulary (Suggest from main dictionary only).
Press OKto save changes and close the dialog Word options (Word Options).
This option is also available in Excel and PowerPoint, where you can enable it in the same way. In Outlook, it is in a different section.