Entry Word: lunacy

Function: noun

Meaning: 1 a foolish act or idea <you want to sneak into school after dark? Thatʼs lunacy!> — see folly 1
2 a serious mental disorder that prevents one from living a safe and normal life <the judge ruled that the lunacy of the accused made him incompetent to stand trial> — see insanity 1
3 lack of good sense or judgment <our friendʼs lunacy makes him of no use in an emergency but very entertaining companion nevertheless> — see foolishness 1