"안녕히 가시고 안녕히 주무세요!"
번역:Goodbye and good night!
"Goodnight" (with no space) is perfectly correct in English when used as a greeting. (E.g. "I'm going to sleep now, goodnight!")
However, it must be two separate words when used as in this example: "It was a good night for walking in the park."
죄송 합니다. I'm not very good at writing in Korean yet.
Generally, it is "good morning", "good afternoon", and "good night". However, sometimes "goodnight" is used. I have never seen "goodmorning" and "goodafternoon" - they require spaces.
Good night (or "goodnight" only when used as a greeting)