How to Say "lunatic" in Spanish
The Spanish word for “lunatic” is “demente” — B2 level.
English → SpanishB2
NounB2
A person who is mad or reckless

Examples
El demente escapó del hospital psiquiátrico.
The madman escaped from the psychiatric hospital.
La demente fue detenida después de causar destrozos.
The lunatic (female) was detained after causing damage.
Referring to People
When 'demente' is used as a noun, it refers to the person. You must use the correct article ('el' for a man, 'la' for a woman) even though the word 'demente' itself doesn't change: 'el demente' / 'la demente'.
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