"Moby Thesaurus II" by Grady Ward
30,260 root words, with 2,520,264 synonyms and related terms.
The largest synonym resource around...

Powered by Enfour's acclaimed "UniDict® Engine", this is the only iOS/macOS dictionary platform with inter-application linking. Meaning "Companion Synonyms" works directly with all other UniDict dictionaries like "American Heritage®", "LDOCE" and "Oxford Dictionaries".

Main features:
● real-time progressive look-up
● wildcard searches for unknown spellings and quizzes
● Scrolling index overview
● partial and wildcard searches
● Hyperlinks from all entries
● Round-trip links out to supported dictionaries *
● bookmarks with notations
● automatic history
● AI boosted anagram generator
● 3D Touch support
● DarkMode support
● iPhone 15 & iOS17 support
● iPad "Fast App Switching" (Multitasking)
● iPad Pro multi-screen and Drag & Drop
● Support for iPhones, iPads, iPods and macOS
● complete offline use - no internet connection is required
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* Tapping on the headwords will start a search in any "Unidict® Engine" dictionary title you have installed.
These searches are 'round-trip', allowing you to return to "Companion Synonyms" through the "Back" button.

If you have just a dictionary and don't have a thesaurus installed, "Companion Synonyms" will act as a replacement for searching out from dictionaries.
This works with:
American Heritage® Dictionary
Australian Oxford Dictionary
Longman Dictionary of Contemporary English
Longman English-Japanese Dictionary
and many more...