Synonyms and antonyms

Roget's Thesaurus

Roget's Thesaurus of English Words and Phrases

Putnam's Word Book A Practical Aid in Expressing Ideas Through the Use of an Exact and Varied Vocabulary

English Synonyms and Antonyms With Notes on the Correct Use of Prepositions

A Dictionary of English Synonymes and Synonymous or Parallel Expressions Designed as a Practical Guide to Aptness and Variety of Phraseology