Learner's definition of LUNACY
[noncount]
1
a : extreme foolishness愚蠢 b : something that is very foolish愚蠢的事 -
Quitting her job was lunacy.她辞去工作真是愚蠢。
-
It would be lunacy [=madness] to try driving home in this storm.想在这样的暴风雨中开车回家真是疯了。
-
His idea was considered total/sheer/complete lunacy.大家认为他的想法十分荒谬。
2
old-fashioned : extreme mental illness : insanity精神错乱