When to use good luck in Korean
Korean: 행운[ haeng-un ]

When to use it
The word (행운) means good luck or a lucky thing that happens. You can use it when something nice happens by chance, or when you want to talk about feeling lucky. It is also used when people wish someone success and good luck.
Example sentences
오늘은 행운이 가득한 날이에요.
Today is a day full of good luck.
시험 전에 친구가 저에게 행운을 빌어 줬어요.
Before the test, my friend wished me good luck.
공원에서 네잎클로버를 보고 행운을 생각했어요.
In the park, I saw a four-leaf clover and thought of good luck.
여행 날에 맑은 하늘은 큰 행운이에요.
A clear sky on a travel day is great luck.
가게에서 마지막 빵을 사서 행운이라고 말했어요.
I bought the last bread at the shop and said it was good luck.
집에 가는 길에 무지개를 보고 행운을 느꼈어요.
On the way home, I saw a rainbow and felt lucky.