Artha Portable is an offline thesaurus with quick access to lookups from any app via a hotkey. It has support for regular expression lookups. It runs from the system tray in the background and can be accessed using a hotkey after highlighting a word in any app.
Full Specifications
What's new in version 1.0.3
General
ReleaseNovember 28, 2012
Date AddedNovember 28, 2012
Version1.0.3
Operating Systems
Operating SystemsWindows Vista, Windows, Windows 2000, Windows 8, Windows 7, Windows XP