Lunacy

/ˈluːnəsi/

Meaning & Definition

noun

the state of being a lunatic; insanity.

His erratic behavior led his family to believe that he was suffering from lunacy.

deliberately foolish or senseless behavior.

The decision to invest all their savings in a failing business was sheer lunacy.

madness or chaotic behavior caused by the phases of the moon (historically considered).

Some people still believe that certain crimes are influenced by lunacy tied to the full moon.

Etymology

The term 'lunacy' comes from the Latin 'lunaticus', meaning 'moonstruck', reflecting the historical belief that the moon could influence mental states.

Common Phrases and Expressions

lunatic fringe

A group of people whose beliefs or behavior are considered extreme or irrational.

lunatic asylum

A historical term for an institution for the care of the mentally ill.

Related Words

lunatic

A person who is considered to be insane.

moonstruck

Affected by the moon; dreamy or crazy.

Slang Meanings

Going off the deep end.

After hearing the news, she went totally lunacy.

Out of one's mind.

He was acting lunacy after staying awake for three days straight.