The word 脏话 is formed by combining two characters: 脏, meaning "dirty" or "filthy", and 话, meaning "speech" or "words". It is a direct and intuitive conceptual compound where the first character acts as a descriptor for the second, creating the meaning "dirty words". This formation visually and notionally attaches the quality of being unclean or impure to language, effectively metaphorizing offensive or vulgar speech as something morally and socially soiled.