User Configuration > Administrative Templates > Microsoft Word 2016 > Miscellaneous
User
HKCU\software\policies\microsoft\office\16.0\common\research\translation
This policy setting allows you to prevent online dictionaries from being used for the translation of text through the Research pane. If you enable or do not configure this policy setting, the online dictionaries can be used to translate text through the Research pane. If you disable this policy setting, the online dictionaries cannot be used to translate text through the Research pane.