Synonyms are different words with identical or at least similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek σύν ("syn") "with" and ὄνομα ("onoma") "name". The words car and automobile are synonyms. Similarly, if we talk about a long time or an extended time, long and extended become synonyms. In the figurative sense, two words are often said to be synonymous if they have the same connotation. an·to·nym [ántənìm] (plural an·to·nyms) noun Word with opposite meaning: a word that means the opposite of another word. For example, "hot" is the antonym of "cold."