This is the 9975th most frequent Korean word.
공부하느라
"Studying" or "busy with studying."
The phrase "공부하느라" is used here to indicate the reason for being busy.
아침부터 공부하느라 정신이 없었어요.
I was busy studying since this morning.
"공부하느라" is employed to explain the cause of not having time.
친구에게 선물 사러 가지 못했는데, 공부하느라 시간이 없었어요.
I couldn't go buy a gift for my friend because I didn't have time due to studying.
Here, "공부하느라" expresses the activity of studying as the reason for insufficient sleep.