For anyone who starts down the open source path, whether it be on Windows or Linux, the first word processor they consider is OpenOffice Writer, which is part of the OpenOffice.org suite. While OpenOffice is certainly a marvelous suite for those with diverse office-like work, or as a replacement for Microsoft Office.
For most people though, the word processor is the only part of the application that is used, and the rest merely goes to waste. Even in Writer, for most people advanced features such as macros, embedded videos, charts etc are an overkill. If you find that your most of the applications in your office suite go underused, or underutilized, it time to consider AbiWord.
AbiWord is much lighter on resources, usually taking half as much memory as OpenOffice.org Writer, and sports a similar interface, so there is not much of a learning curve. Even if you are switching straight from Microsoft Word, you will find that it hardly requires any time to get used to.
Its simplicity does not in any way sacrifice its flexibility though. A large number of plugins exist for extending AbiWord to enable support for more formats, and for adding features. Besides plugins AbiWord supports a great many languages for its interface, and for spelling check. In fact it was the first open source word processor to support grammar checking.
If you have need only for a simple work processor without all the bloat, and with the minimal features required for day to day documentation tasks, you will find that AbiWord will satisfy all your needs.