This is the 338th most frequent Korean word.
없고
"없고" means "and not existing" or "and there is no."
The "없고" indicates the absence of people ('없다' in the context of existence) and connects the resulting calmness.
그 가게에는 사람들이 없고 조용했어요.
There were no people in the store, and it was quiet.
The "없고" starts the sentence by stating the absence of books ('책은 없다'), leading to the contrasting second part about magazines.
책은 없고 잡지만 조금 있었어요.
There were no books, but there were a few magazines.
The word '없고' is used here to connect the clause '나느 시간이 없어요' (I don’t have time) with '일이 많아요' (I have a lot of work), showing a contrast in situations.