languor

1. N-UNCOUNT Languor is a pleasant feeling of being relaxed and not having any energy or interest in anything. 慵嬾; 悠然[文學性]

How easy it is for even an energetic person to lapse into a pleasant languor. 讓一個即使精力充沛的人頹廢到慵嬾的狀態是多麽的容易。