Code words are words or phrases that are used to represent a secret or hidden meaning. Synonyms for code words could include jargon, slang, argot, lingo, catchphrases, passwords, and signals. Jargon refers to specialized language used in a specific profession or group, while slang is more casual language used by younger generations. Argot is a more specific type of slang used by criminals or other secretive groups. Lingo and catchphrases refer to commonly used words or phrases within a particular community. Passwords and signals are specific terms used for security or secret communication. All of these synonyms can be used to describe words or phrases used to express a hidden meaning.