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see insanityinsanity,
mental disorder of such severity as to render its victim incapable of managing his affairs or of conforming to social standards. Today, the term insanity is used chiefly in criminal law, to denote mental aberrations or defects that may relieve a person from the legal
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an obsolete term for somnambulism, derived from ancient notions concerning the moon’s effect on the mind.


(formerly) any severe mental illness
References in classic literature ?
You talk of the lunacy of the Pyncheons; is it contagious?
A mind disposed to lunacy would readily be led away by such suggestions - especially if chiming in with favorite preconceived ideas - and then I called to mind the poor fellow's speech about the beetle's being "the index of his fortune.
A Chancery judge once had the kindness to inform me, as one of a company of some hundred and fifty men and women not labouring under any suspicions of lunacy, that the Court of Chancery, though the shining subject of much popular prejudice (at which point I thought the judge's eye had a cast in my direction), was almost immaculate.
Sherlock Holmes, the well known consulting expert, have each come to the conclusion that the grotesque series of incidents, which have ended in so tragic a fashion, arise from lunacy rather than from deliberate crime.
I came, Katharine, to ask whether we can't return to the position we were in before this--this season of lunacy.
A single kink in my brain," Thomson continued, "a secret weakness, perhaps even a dash of lunacy, and I might be quite reasonably the master-spy of the world.
Men he had seen in love impressed him as lunatics, and lunacy was a thing he had never considered worth analyzing.
the one streak of lunacy in what was otherwise an eminently rational mind?
The humblest wayside juggler in India could mystify them to the verge of lunacy.
We are engaged at this very moment in getting a commission of lunacy on her husband.
In my case, healthy, normal, young, full of the joy of life, the suggestion to kill myself was unusual; but it must be taken into account that it came on the heels of a long carouse, when my nerves and brain were fearfully poisoned, and that the dramatic, romantic side of my imagination, drink-maddened to lunacy, was delighted with the suggestion.
But Carlisle people knew nothing of this--would have thought him tinged with mild lunacy if they had known.