Nani? is described as 'Search by kanji, reading and meaning. Using free JMdict dictionary by EDRDG (Electronic Data Research and Development Group). Download dictionary from "Manage Dictionaries" menu' and is a Dictionary in the Education & Reference category. There are four alternatives to Nani? for Android, Online / Web-based, Windows and Windows Phone. The best alternative is Takoboto, which is free. Other great apps like Nani? are Sumatora (Free, Open Source), Akebi Japanese Dictionary (Free) and WWWJDIC for Android (Free, Open Source).
An offline Japanese dictionary for Android using JMdict (Japanese-Multilingual Dictionary). Display exact term/term at the beginning/term included reverse search from the translation in any of the supported languages. Also search in romaji, hiragana and katakana.
Japanese-English offline dictionary with handwriting recognition. No ads. Dictionary data is KANJIDIC from The Electronic Dictionary Research and Development Group, and example sentences from The Tatoeba Project.
Front end for online Japanese dictionary service Jim Breen's WWWJDIC hosted by Monash University. Search kanji by radicals. Pronunciation by text to speech. Includes sample sentences. User handwriting recognition via Kanji Recognizer (separate, non-free app).