Crank (person)

"Crank" is a pejorative term used for a person who holds an unshakable belief that most of his or her contemporaries consider to be false. A crank belief is so wildly at variance with those commonly held as to be considered ludicrous. Cranks characteristically dismiss all evidence or arguments which contradict their own unconventional beliefs, making any rational debate a futile task and rendering them impervious to facts, evidence, and rational inference.

Common synonyms for "crank" include crackpot and kook. A crank differs from a fanatic in that the subject of the fanatic's obsession is either not necessarily widely regarded as wrong or not necessarily a "fringe" belief. Similarly, the word quack is reserved for someone who promotes a medical remedy or practice that is widely considered to be ineffective; this term, however, does not imply any deep belief in the idea or product they are attempting to sell. Crank may also refer to an ill-tempered individual or one who is in a bad mood, but that usage is not the subject of this article.

Although a crank's beliefs are ridiculous to experts in the field, cranks are sometimes very successful in convincing non-experts of their views. A famous example is the Indiana Pi Bill where a state legislature nearly wrote into law a crank result in geometry.

Old English cranc- is preserved in modern English crankshaft, and obsolete crancstæf "a weaver's instrument". It is from a Proto-Germanic stem *krank- meaning "bend". German krank has a modern meaning of "sick, ill", evolved from a former meaning "weak, small". English crank in its modern sense is first recorded 1833, and cranky in a sense of "irritable" dates from 1821. The term was popularised in 1872 for being applied to Horace Greeley who was ridiculed during his campaign for the U.S. presidency. In 1882, the term was used to describe Charles Guiteau who shot U.S. president James Garfield.

In 1906, Nature offered essentially the same definition which is used here:

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