Like pleonasm, tautology is often considered a fault of style when unintentional. Tautology and pleonasm are not consistently differentiated in literature. The term pleonasm is most often, however, employed as synonymous with tautology. Sometimes editors and grammatical stylists will use "pleonasm" to describe simple wordiness. Syntactic pleonasm occurs when the grammar of a language makes certain function words optional. Semantic pleonasm is a question more of style and usage than of grammar. It contrasts with periphrasis, aureation and pleonasm. Pleonasm involves using more words than necessary to describe an idea.