Meaning: This means to speak or utter words that express a wish for a pleasing or desirable period of darkness between sunset and sunrise. It's like saying,
Choice of Words: The word "say" means to speak or utter words. "Good" means something that is pleasing or desirable. "Night" is the period of darkness between sunset and sunrise. Together, "say goodnight" means to speak or utter words that express a wish for a pleasing or desirable period of darkness between sunset and sunrise.
No related expressions found.