First, my Word/Office is 15.11.2 and Auto Update and Manual Update tell me there is no update available. I know there are more recent version, but this is all I can get. I've tried in Word and Outlook to update and this is it for now.
My Macbook Pro is on Sierra 10.12.2.
I use Outlook and PowerPoint just fine, so this issue is only with Word. I have to wait 2 - 3 minutes after opening a file to work on. After typing a bit I'll get a spinning beach ball and have to wait minutes again. Over and over this goes. I can open a new document and get this behavior, so it's not a corrupted file I am trying to work on.
I notice when I go to open a file, the window defaults to SharePoint at my University instead of On my Mac. Perhaps this is related (and there are no files at the university SharePoint link.