A family of Microsoft word processing software products for creating web, email, and print documents.
If you have Time Machine running you can restore a previous build of just Microsoft Word.app
Before doing that, go to Word > Help (or any Office app Help) and choose Check for Updates to launch AutoUpdate. Set AutoUpdate to manual so it doesn't try to bring you back up to date as soon as you restore an old build.
If you don't have a Time Machine backup, you can download individual installers from this page:
https://docs.microsoft.com/en-us/officeupdates/update-history-office-for-mac