disapproval If you describe someone's behaviour or ideas as lunatic, you think they are very foolish and possibly dangerous. the operation of the market taken to lunatic extremes. a country spurned until now by all except the more lunatic of journalists and adventurers. = mad, insane
disapproval If you describe someone as a lunatic, you think they behave in a dangerous, stupid, or annoying way. Her son thinks she's an absolute raving lunatic