relapse

名词 relapse:

1. a failure to maintain a higher state
   同义词：backsliding, lapse, lapsing, relapsing, reversion, reverting

动词 relapse:

1. deteriorate in health
   同义词：get worse
2. go back to bad behavior
   同义词：lapse, recidivate, regress, retrogress, fall back

re.lapse

v.intr.（不及物动词）
re.lapsed,re.laps.ing,re.laps.es
To fall or slide back into a former state.
恢复：回到或陷入以前的状况
To regress after partial recovery from illness.
复发：疾病部分康复以后再次退化
To slip back into bad ways; backslide.
故态复萌：重新滑入不好的方式；堕落
n.（名词）

A falling back into a former state, especially after apparent improvement.
重陷：退回到以前的状况，尤其是取得很明显的改善以后

来源：
Middle English relapsen [to forswear]
中古英语 relapsen [发誓抛弃]
from Latin rel3bo rel3ps- [to fall back gradually]
源自 拉丁语 rel3bo rel3ps- [逐步地退回]
re- [re-]
re- [前缀re-]
l3bo [to slide]
l3bo [滑]

【引伸】
relaps.er
n.（名词）