User Configuration > Administrative Templates > Microsoft Word 2016 > Word Options > Proofing
User
HKCU\software\policies\microsoft\office\16.0\word\options
This policy setting allows you to configure when the background grammar check is started. If you enable this policy setting, you may specify the delay, in milliseconds, before the background grammar check is started. This setting only applies when Word is running in a terminal server session. If you disable or do not configure this policy setting, Word will behave normally when in a terminal server session.