KWord is a thing, and the only reason it's not still under active development is because enthusiasm for development dried up after the acrimonious KOffice/Calligra split. In fact, it was the only part of the KOffice suite that was allowed to keep its name after the split.
And there's also AbiWord, which is still under active development.
Or speaking of which, all the gazillion office suites with Office in the name.
KWord and AbiWord don't use "Word" as a standalone, well, word. They're clearly not Word. You're not going to confuse them, and that's the point.
And "office" became the term for an office suite, the way "calendar" and "contacts" and "word processor" are just descriptive terms too.
But "Docs" and "Word" have a clear, obvious distinctiveness that "office" and "calendar" don't. "Word" and "Docs" don't inherently mean "word processor". Heck, OpenDocs.com is for legal forms, not word processing.
I really don't know what you're arguing. Go ahead, start a word processor named just "[Company name] Word" with the space and get sued by Microsoft and lose. You don't really think you'll win, do you? This is not a controversial or blurry area of trademark law.
And there's also AbiWord, which is still under active development.
Or speaking of which, all the gazillion office suites with Office in the name.