lunatic

Universal Words noun, adjective noun 1 a person who does crazy things that are often dangerous: This lunatic in a white van pulled out right in front of me! 2 (old-fashioned) a person who is severely mentally ill (the use of this word is now offensive): a dangerous / homicidal lunatic ORIGIN Originally from the Latin lunaticus (luna = moon), because people believed that the changes in the moon caused temporary madness. adjective crazy, ridiculous or extremely stupid: lunatic ideas * a lunatic smile IDIOMS the lunatic fringe noun [sing.+sing./pl.v.] (disapproving) those members of a political or other group whose views are considered to be very extreme and crazy: They stressed that only the lunatic fringe of the movement was involved in the incident.