lu·na·tic

– noun
1. an insane person.
2. a person whose actions and manner are marked by extreme eccentricity or recklessness.
3. a person legally declared to be of unsound mind and who therefore is not held capable or responsible before the law.
–adj.
4. insane; demented; crazy.
5. characteristic or suggestive of lunacy; wildly or recklessly foolish.
6. designated for or used by the insane.
7. gaily or lightheartedly mad, frivolous, eccentric, etc.

lu·na·cy

– noun
1. insanity; mental disorder.
2. intermittent insanity, formerly believed to be related to phases of the moon.
3. extreme foolishness or an instance of it.
4. unsoundness of mind sufficient to incapacitate one for civil transactions.