Arcus Dictionary Pro is a fast English dictionary with 185000+ words, definitions and synonyms available offline. There are no ads, and no permissions.
The pro versions have extra features compared to the basic free version: search web dictionaries, voice search, random word widget, 10,000+ more definitions and sample sentences where available.
It is designed to be easy to use and give you the top and most common results for your query. All you need to do is start typing to get results instantly. By default the more probable matches are displayed first although there is an option to display results purely alphabetically too.
The dictionary also supports pronunciations for definitions, a favourites feature, word hyperlinking, sharing and customisation options.