Noun: An individual who is incapable of acting rationally due to mental illness, usually accompanied by overt bizarre behavior. Usually used humorously or informally.
Adj: Behavior that is manifestly irrational and disturbing to others
The action of the United States Congress in voting to pass a bill that would strike this word Lunatic from the U.S. Code.
They do not provide a replacement for this term, therefore if there are existing laws that protect those who do not have the ego or cognitive ability to care for themselves, any governmental protection will be removed.
The reason given is that the word has an archaic root, which would include eliminating a fairly large part of the English vocabulary, it would be decimated (look that one up