The Vietnamese word "đau đáu" describes a state of feeling anxious or being on tenterhooks. It captures the sense of persistent worry or restlessness about something that is uncertain or troubling.
Tôi cảm thấy đau đáu khi chờ đợi kết quả kỳ thi.
("I feel anxious while waiting for the exam results.")
Cô ấy luôn đau đáu về sức khỏe của cha mình.
("She is always worried about her father's health.")
In summary, "đau đáu" is a useful word to express feelings of anxiety and concern in Vietnamese.