Merriam-Webster's Dictionary of Synonyms

Merriam-Webster's Dictionary
Good communication starts with choosing the right word--not always an easy task when the choise is between words of closely related meaning. Merriam-Webster's Dictionary of Synonyms makes the task easier by providing full discussions of synonymous terms and by describing the subtle distinctions that make one word more appropriate than another in a particular context.

Merriam-Webster's Dictionary of Synonyms:
A Dictionary of Discriminated ...
By Merriam-Webster, Inc, Merriam-Webster, Merriam-Webster, Philip B. Gove