crazy, looney, loony, weirdo - someone deranged and possibly dangerous

bedlamite - an archaic term for a lunatic

pyromaniac - a person with a mania for setting things on fire

madwoman - a woman lunatic

diseased person, sick person, sufferer - a person suffering from an illness

adventurer, venturer - a person who enjoys taking risks

tearaway - a reckless and impetuous person

colloquialism - a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech

insane - afflicted with or characteristic of mental derangement; "was declared insane"; "insane laughter"