If you feel obligated to do something, you feel that it is your duty to do it. If you are obligated to someone, you feel that it is your duty to take care of them. 有责任的; 有义务的
adjective [原级]有义务的;责无旁贷的
I felt obligated to let him read the letter. 我觉得有责任让他读到这封信。