Contronyms were not among the categories of “nyms” I learned as a child. I know all about synonyms, homonyms, and antonyms. So I was surprised when I recently learned about contronyms. Contronyms are words that are their own antonyms (in fact, they are sometimes called autoantonyms). That’s right, the same word can have two opposing or contradictory meanings. Think of dust. Dust can mean to add fine particles to something: The plane was dusting the field. Or it can mean to remove fine particles. I needed to dust my office after the windstorm. Because contronyms have contradictory meanings, writers must depend on context to make sure the reader understands which meaning the writer intended. Context can come in either the paragraph or the s...