dict.cc
Free
dict.cc is a free, multilingual online dictionary. The site's database can also be downloaded and used offline.
Aard Dictionary
Open Source
Aard Dictionary is a free, fast word lookup program.
Tagaini jisho
Open Source
Tagaini Jisho is a free, open-source Japanese dictionary and kanji lookup tool that is available for Windows, MacOS X and Linux.
Compare StarDict with alternatives
Compare Tagaini jisho and StarDict and decide which is most suitable for you.
Compare Aard Dictionary and StarDict and decide which is most suitable for you.