MSA – Dictionary that provides not only English translations, but also parses words to show you the part of speech and root. If you come across a verb, for example, and can’t figure out what the base form or measure of the verb is, type it in and see a list of possible meanings and conjugations.
All The Arabic You Never Learned The First Time Around
MSA – Grammar reference and drills for non-beginning learners.
Fuzzy Arabic Dictionary
Look up Arabic words without needing to know how to spell them. Just type a word out as it sounds to you in English.
Forvo: Arabic pronunciation dictionary
Crowd-sourced pronunciation of thousands of words and phrases. Request pronunciations from native speakers.
CA – User-generated dictionary of colloquial Arabic with colloquial / slang expressions organized by country.
The Living Arabic Project
ECA / LCA / (MSA) – Online Egyptian Arabic, Levantine Arabic, and Classical Arabic dictionaries.
MSA (ECA) – Order the dictionaries to search by preference, then search for a root. Features the Hans Wehr Dictionary of Modern Written Arabic, A Dictionary of Egyptian Arabic (Hinds/Badawi), among many others.
MSA – Bilingual (Arabic – English / French / Portuguese / Spanish / Turkish / Persian) dictionaries, monolingual Arabic dictionary, Arabic names dictionary, forum, and other online tools.