Others

Fix OneNote Spelling Errors for Words with Underscores

Maira Mehtab Sep 20, 2026 869 views

Question details

The user wants to prevent OneNote from marking words connected by underscores as spelling errors, or have it check each component of the word individually.

Product: Microsoft OneNote
Device & OS: not provided
Scenario: Writing technical documentation, code snippets, or programming function names within a OneNote notebook.
Observed behavior: OneNote flags words containing underscores as misspelled, as it currently lacks a built-in feature to ignore them or check the underscore-separated components separately.

Before you start

Before proceeding, determine whether you want to disable spell check globally for the entire application or just for specific blocks of technical text.

Solution 1Recommended

Disable Spell Check for Specific Text Blocks

Use this workaround to manually hide red squiggly lines for code snippets without turning off spell check globally.

Since OneNote does not natively support ignoring words with underscores, the best workaround is to tell OneNote not to check the spelling of your code blocks.

Select the target text

Highlight the code snippet or the text containing words with underscores that are being marked as errors.

Open Language Settings

Navigate to the 'Review' tab on the top ribbon and click on 'Language', then select 'Set Proofing Language'.

Disable spelling checks

In the Language pane, check the box that says 'Do not check spelling or grammar' and close the pane.

Formatting Tip: You can save this un-proofed text style using the Format Painter to quickly apply it to future code snippets.

Solution 2

Submit a Feature Suggestion to Microsoft

Officially request an update to OneNote's proofing engine to support underscore-separated words.

Free Microsoft Office alternative

Switch to WPS Office for Technical Writing and Documentation

If OneNote's lack of advanced formatting options for technical writing is slowing you down, consider using WPS Office. It acts as a highly capable, free, and lightweight Office alternative with flexible spell-check settings and seamless format migration.

1. Download the Installer: Visit the official WPS Office website and download the free version for your operating system.
2. Install the Application: Run the setup file and follow the quick on-screen instructions to complete the installation.
3. Start Creating Documents: Launch WPS Writer or Note to start organizing your technical documentation without restrictive spelling errors.

Fully compatible with Microsoft Word, Excel, and PowerPoint formats.Advanced, customizable spell-check options suitable for technical writers and developers.Lightweight application that runs smoothly across multiple devices and platforms.Free to use with a familiar, easy-to-navigate user interface.

Frequently Asked Questions

Can I add underscore-separated words to the OneNote custom dictionary?

Yes, you can right-click any flagged word and select 'Add to Dictionary'. However, this can become tedious if you are writing dynamic code with many unique variable or function names.

How do I turn off spell check entirely in OneNote?

To disable global spell checking, go to File > Options > Proofing, and uncheck the 'Check spelling as you type' box. This will remove all spelling error indicators across all notebooks.

Is there a native markdown or code block feature in OneNote?

OneNote does not currently have a native code block feature that automatically ignores formatting and spelling. Users generally rely on custom fonts, disabling proofing for specific blocks, or third-party add-ins to handle code snippets.

Office Quick Solutions