AardDict, http://aarddict.org/ is an offline dictionary app primarily used for browsing offline dumps of Wikipedia in various languages. However, The latest version of their Wiktionary dump http://aard.tk/enwikt contains the translations section of each wiktionary artilcle. This has been extremely helpful to me when I’ve been somewhere with no wifi or 3G signal.
I use DictData as offline Dictionary on my Android.
Thanks Odiernod. I have a tough time to find good dictionary for my Ubuntu Desktop and Android phone. AardDict is pretty cool, personally. I love it.