Homonym: crank (Irritable)
A "crank" is a mechanical device used to convert rotational motion into linear motion or vice versa. It typically consists of a handle attached to a shaft that rotates around a fixed point. Cranks are commonly found in various machines, such as bicycles and engines, where they help to transfer energy efficiently.
In a different context, "crank" can also refer to a person who holds an eccentric or unorthodox opinion, often in a passionate manner. This usage is frequently associated with individuals who advocate for unconventional ideas, such as certain scientific theories or political beliefs.