Definition of lunatic
1 dated a : affected with a severely disordered state of mind : insaneb : designed for the care of mentally ill people a lunatic asylum
2 : wildly foolish a lunatic idea lunatic behavior
Examples of lunatic in a sentence
He hatched a lunatic plot to overthrow the government.
another of his lunatic ideas
Origin and Etymology of lunatic
Middle English lunatik, from Anglo-French or Late Latin; Anglo-French lunatic, from Late Latin lunaticus, from Latin luna; from the belief that lunacy fluctuated with the phases of the moon
First Known Use: 14th century
LUNATIC Defined for Kids
Definition of lunatic for Students
1 : an insane person
2 : a person who behaves very foolishly That lunatic went through a red light.
Medical Definition of lunatic
: an individual marked by a severely disordered state of mind
Legal Definition of lunatic
: an insane person —used especially formerly
Seen and Heard
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