Microsoft Word for Android is a pre-release version of Microsoft's official Word app.
This release has been optimised for phones, and although smaller screens are never going to be the ideal way to access Word, there's plenty to like here. The app looks and feels much like Office elsewhere, opens the same documents (with images, charts, SmartArt, equations and more), preserves your formatting, and gives you easy access to your documents on OneDrive (+ For Business), Dropbox and SharePoint.
Unlike the previous enterprise release, there's no need for an Office 365 subscription, although you will have to sign up as a beta tester.
To get started, sign up at the official Microsoft Office for Android community (the Download link here will point you in the right direction).
Microsoft says you may then have to wait up to 4 hours for Google play to replicate your tester's permissions.
Once that's done - or if you want to try it anyway, see what happens - follow the "Word Preview" link on the site.
If Google says "you are a tester" and displays your login name, follow their Download link to grab a copy (it'll auto-upload after that so life will become much easier).
If you're not recognised as a tester yet - or you've tried installing and got an "incompatible" message - come back in an hour or so, or check the other messages and FAQs on the Community page for more advice.
It can take a little while to get hold of the preview, but if you're a regular Office user then it's worth the effort.