Korean "간지난다" sounds like [Ganji-nanda] without putting any stress on the vowels.
It means "looking good, looking great, looking fit, or looking fly".
For example, when you go shopping with some friends, one of your friends put on some clothes and he or she looks great. In this kind of situation, you can use this expression.
It is rather informal, so be careful not to use it in formal situation.
