WordWeb is a free offline English dictionary and thesaurus that offers synonyms, related words, and a great search function without any advertisements. The app includes a comprehensive database of 285,000 words, phrases, and derived forms, 225,000 word sense definitions, 70,000 usage examples, and 85,000 text pronunciations. It also provides synonyms, similar and related words, and supports N. American, British, Australian, and international English.

The app's intelligent word entry suggests possible correct spellings as you type, as well as listing words that sound the same or are often confused. Additional features include the ability to drill down on any word in a definition, full bookmark support, and history. The search features include alphabetical listing, spelling suggestions, sounds-like and often-confused, fast pattern-matching search (*, ?, vowel and consonant), and filter search results by noun, verb, adjective, adverbs.

The database includes proper nouns and common abbreviations in addition to English vocabulary (e.g. LOL, Oxford, JPEG, Webster, UNHCR, etc.). You can quickly look up words from within other apps by selecting the word, then selecting WordWeb from the pop-up menu (requires Android M and higher). No Internet connection is required to use WordWeb, and it's free.

Overall, WordWeb is a comprehensive and user-friendly offline English dictionary and thesaurus that offers a great search function and a wide range of features. It's a great alternative to dictionary.com and other similar apps, and it's definitely worth checking out.