[Mashiro]

As mentioned in another Windows 10 related topic the Windows Defender that is built into Windows 10 nowdays (actually since a few years and builds) is a multi component system in the core of Windows 10 that acts as a security and protection center for the whole OS. So the Windows Defender antivirus is one component of it and while it cannot be removed it can be disabled pretty easy.

Windows 10 Pro or higher:
Disable Windows Defender antivirus via the Group Policy editor (GPO)

Windows 10 Home or higher (might not work now or in the future):
Disable Windows Defender antivirus via registry keys (regedit)

Don't attempt to fiddle around with the Windows Defender services in services.msc applet as they cannot be disabled.

Before applying any of these solutions you need to disable the anti tamper feature of Windows Defender antivirus. If you don't disable it and apply the solution(s) they simply won't have an effect and the antivirus component will still run regardless.

Additionally you will have to disable the Windows Defender trayicon in the task manager (autostart tab) and disable the Windows notifications in the control panel (not the Settings app!).

Windows Defender Trayicon


Disable antivirus notifications:
1. On the search tab, type "Security and Maintenance".
2. Choose "Change Security and Maintenance settings".
3. Uncheck the notifications that you don't want to pop-up (Antivirus in your case).