crank2

noun

• 1an eccentric person, especially one who is obsessed by a particular subject:when he first started to air his views, they labelled him a crank [as modifier]:I am used to getting crank calls from conspiracy theorists
• North American a bad-tempered person.

  [ mid 19th century: back-formation from cranky]

• 2 literary a fanciful turn of speech.

  [ late 16th century: perhaps from a base meaning 'bent together, curled up', shared by Old English cranc (see crank¹)]