insanity \In*san"i*ty\, n. [L. insanitas unsoundness; cf. insania insanity, F. insanite.] 1. The state of being insane; unsoundness or derangement of mind; madness; lunacy. Dictionary.com   In law, is a mental defect or disorder sufficient to prevent a person from knowing the difference between right and wrong conduct or from understanding the nature of his or her actions.

If you had Java you'd see a really cool lava lamp here!