The easy powershell method is here from an answer I posted on a question later marked duplicate for this.
The easiest way to do this would be to use powershell to disable it, the command you probably want is this:
Set-MpPreference -DisableRealtimeMonitoring $true
Get-Service WinDefend | stop-service
For an article on using powershell to disable/enable Windows Defender check here: http://wmug.co.uk/wmug/b/pwin/archive/2015/05/12/quickly-disable-windows-defender-on-windows-10-using-powershell
Here is the technet article for a more detailed look at available defender cmdlets: https://technet.microsoft.com/en-us/library/dn433280.aspx