This is the 27th most frequent Korean word.
없다
To not exist; to not have.
Here, 없다 indicates the absence of an object (money) in a specific location (wallet).
내 지갑에 돈이 없다.
There is no money in my wallet.
In this sentence, 없다 is used to describe the lack of a quality or characteristic (being fun).
그는 재미가 없다.
He is not fun.
없다 here expresses the nonexistence of something to do or engage with (things to see) in a specified place.