Notdef

The notdef icon represents an undefined or unknown state, often used to symbolize errors, warnings, or alerts.

In software and online platforms, the notdef icon is commonly used in error handling systems, debugging tools, or alert notifications. For example, it may be used in conjunction with error messages, warning signs, or alert notifications.

From a UX perspective, the notdef icon communicates a sense of uncertainty or error, helping users understand that they are interacting with features or systems that require attention or correction.

Notdef is one of 164 icons in Font Awesome 6 Regular, made by Dave Gandy and released under CC BY 4.0. It is drawn on a 384 × 512 grid.

Sign in (it's free), then open Get icon, Install with shadcn CLI, and pick your package manager to copy the command. It adds NotdefIcon to components/icons/fa6-regular-notdef.tsx: one file, a size prop (24 by default) and every SVG prop, with no icon package.

Copy it as React (from Get icon, or the Code section): a typed NotdefIcon component you paste into your project, with no package to install. Only the icons you import reach your bundle. It works in Next.js and any React app.

Open Get icon, then Copy as code, and pick Vue, Svelte, Angular, Solid or Preact; the Code section shows each one too. Every version is one self-contained component with the SVG inside, and SVG and data URL copies are there for plain HTML and CSS.

With Pro, the shadcn.io MCP server lets Claude Code, Cursor or any MCP client find the Notdef icon, or any of 164 Font Awesome 6 Regular icons, and install it from a prompt.

It's drawn in currentColor, so it takes the text color wherever you use it: a class like text-primary recolors it. To bake a color in, set one in Customize before you copy.

Set width and height on the component, or a class like size-6. It's drawn on a 384 × 512 grid, so it stays sharp at any size. Customize also sets the size it exports at, its padding and rotation.

Yes. It follows the text color, so with text-foreground (or any theme token) it changes with your light and dark themes. The icon is a vector, so it needs no separate dark asset.

Next to a visible label it's decoration: add aria-hidden="true" so screen readers skip it. Standing alone, as in an icon button, give the button a name instead, like aria-label="Notdef", so screen readers say what it does.

Yes. NotdefIcon passes every SVG prop to the svg element, so <NotdefIcon aria-hidden="true" /> works, and so do role="img" with aria-label, or a title child, when it carries meaning on its own.

Yes. Open Get icon, then Download file: SVG for code or design tools like Figma; PNG, WebP or JPEG at 512px; or an ICO favicon with 16, 32 and 48px inside. Each one uses what you set in Customize.

Yes, with credit: CC BY 4.0 asks you to credit the author (Dave Gandy) where you use the icons. The full terms are in the license, linked on this page.

Yes. CC BY 4.0 asks you to credit the author where you use the icons, for example "Icons by Dave Gandy, CC BY 4.0" on an about or credits page.

Yes. Copying and downloading it is free, and the shadcn CLI install only needs a free account.

2 other libraries draw an icon called Notdef. The Other libraries section on this page shows each one, so you can compare them and open the one that fits your style.

Its tags are warning, alert and error. Each tag page lists the icons that carry it from every library, which is the quickest way to find a match for Notdef in another set.