Cycloalkyl is a term used in organic chemistry to describe a closed ring hydrocarbon compound that only contains carbon and hydrogen. However, there are a few other words that can be used as synonyms for cycloalkyl. One possible word is "cycloparaffin" which has a very similar meaning to cycloalkyl. Another term that can be used is "cycloralkane," which is a type of hydrocarbon that contains a ring of carbon atoms and hydrogen atoms. The word "cyclic hydrocarbon" is another synonym that can be applied to cycloalkyl. All of these words are used to describe compounds that are commonly studied in organic chemistry.