The thesaurus service for WPS Office's Spell Checker feature is provided by this app plugin. WPS Office Extra Goodies could increase the precision of spell-checking.

Four thesaurus are now available: English, Russian, Portuguese, and Spanish.

Please install WPS Office first (download link: https://play.google.com/store/apps/details?id=cn.wps.moffice eng) before installing it if you want to give it a try. With WPS Office installed on your devices, it must offer service.

How to Use: 
This app plugin, WPS Office Extra Goodies, has no "face" after installation because there won't be an icon added to your device's desktop. 
This thesaurus service will be called according to your language when you use the Spell Checker function in WPS Office.