Mu'jam is an Arabic-Arabic and English-Arabic dictionary app developed by Rdeef. With over 200,000 words, the app provides synonyms, antonyms, and an advanced algorithm to find possible roots. The app also features a built-in font and support for Arabic text rendering.

One of the most interesting features of Mu'jam is the ability to share content from other applications to get definitions. Additionally, if you search for a word in English, the app will provide its Arabic translation. The app does not require an internet connection and keeps a history of your last searches.

For Arabic learners, Mu'jam offers a night mode for better reading and different rendering colors for Tashkeel (diacritics) to recognize them easily. The app also provides daily notifications for a random Arabic word, which can be turned off. Lastly, there is a button to show a random word.

Mu'jam is an excellent choice for anyone looking for a comprehensive Arabic dictionary.