Affected by lunacy; insane; mad; crazy; demented.
Of or pertaining to, or suitable for, an insane person; evincing lunacy; as, lunatic gibberish; a lunatic asylum.
A person affected by lunacy; an insane person, esp. one who has lucid intervals; a madman; a person of unsound mind.
a reckless impetuous irresponsible person
insane and believed to be affected by the phases of the moon
a person who comes under the legal qualifications of insanity
a person whose whole world is confined in himself
A lunatic (colloquially: "loony") is commonly used term for a person who is mentally ill, dangerous, foolish or unpredictable, a condition once called lunacy.