lethargy
/ˈleθədʒɪ/noun
mass noun
1- a lack of energy and enthusiasm无精打采, 懒散乏力：
there was an air of lethargy about him
他一副没精打采的样子
in sing. she might have sunk into a lethargy.她或许已经变成一个缺乏生气、精神委顿的人了。
1.1
- Medicine a pathological state of sleepiness or deep unresponsiveness and inactivity【医】昏睡, 嗜眠。
词源
late Middle English: via Old French from late Latin lethargia, from Greek lēthargia, from lēthargos 'forgetful'， from the base of lanthanesthai 'forget'.