How to say good night in Hindi
Search this and you get शुभ रात्रि. It is correct, and it is also the phrase most families would never say to each other going up the stairs. Same shape as धन्यवाद: the dictionary is right and the living room is different. Here is both.
The textbook one
शुभ means auspicious, रात्रि is night. It fits a message, a host you just met, an elder you are being careful with. It is not wrong at home, it just reads a little ceremonial.
What gets said at home
And honestly, plenty of Hindi-speaking families just say "good night" in English. That is not laziness, it is how bilingual homes work. Nobody will think you failed.
Related evening lines
कल is a useful oddity: it means both yesterday and tomorrow, and the verb tense tells you which. मिलते हैं is present, so this one points forward.
In Gujarati
આવજો literally invites the person to come again, which is a nicer way to part than "bye". It carries most evening goodbyes in a Gujarati house.