All power of fancy overreason is a degree of
insanity. --Johnson.
Without grace The heart's insanity admits no cure.
--Cowper.
2. (Law) Such a mental condition, as, either from the
existence of delusions, or from incapacity to distinguish
between right and wrong, with regard to any matter under
action, does away with individual responsibility.
Syn: Syn>- {Insanity}, {Lunacy}, {Madness}, {Derangement},
{Aliention}, {Aberration}, {Mania}, {Delirium},
{Frenzy}, {Monomania}, {Dementia}.
Usage: Insanity is the generic term for all such diseases;
lunacy has now an equal extent of meaning, though once
used to denote periodical insanity; madness has the
same extent, though originally referring to the rage
created by the disease; derangement, alienation, are
popular terms for insanity; delirium, mania, and
frenzy denote excited states of the disease; dementia
denotes the loss of mental power by this means;
monomania is insanity upon a single subject.