Thesauruses present a catalog of synonyms from which we may pick and choose words to put into our writing, but a thesaurus used alone is a very bad thing because there is no such thing as a true synonym. Every word has its particular place in the language.
To present a group of words that allegedly say the same thing, as one finds in thesauruses, and then grab one word and insert it into a sentence because one thinks it to be synonymous with the other word… well, one can easily choose the wrong term. It is easy to ignore the subtle differences, but this can make for sloppy use of the language. In looking at a Roget-type thesaurus, a close examination of the clusters will make the user aware of the fine distinctions between synonyms, but the user will soon recognize that few words are exactly interchangeable. The thesaurus should be used in conjunction with a good dictionary whenever a selected word or phrase is unfamiliar. There really is no such thing as a true synonym. Even though the meanings of two words may be the same or nearly the same, they almost never are the same in connotation, distribution, and frequency. “House” and “home” may be offered as synonyms for each other, but we all know that they are not the same.