I use renshuu's dictionary all the time (especially right now that I'm briefly visiting Japan). Fortunately, I have a wifi puck, but I can't help thinking how unfortunate it would be if I could not use the dictionary function if I had no wifi/mobile data
I love all the features the dictionary has (like the Grammer dictionary, and the example sentences, and of course pitch diagrams)
For anyone who needs this, there is an app called “imiwa?” that bundles WWWJDIC with conjugation software and example sentences from tatoeba. It’s not renshuu, but it’ll do in a pinch.
For dictionary apps apart from Renshuu, I use Takoboto. If you also add Chase Colburn's Kanji Study app, Takoboto integrates that, but you can use them separately.
Alternatively, on the Kindle app are some dictionaries you can get for free. Some of them have their differences, but if you can navigate your way through that, it shouldn't be a problem.
