How to say "crank" in Japanese

• クランクCommon
  nounCovers the mechanical sense of 'crank': a device that converts rotary motion. Use this for machinery, engines, and engineering contexts; it is a loanword written in katakana.
• 変人へんじんCommon
  nounCovers the human sense of 'crank': a person with strange habits or views. This is the ordinary, everyday word for an eccentric, and the one learners will most often want for calling someone a crank.
  多おおくの科学者かがくしゃは世間せけんに変人へんじん呼よばわりされている。↗

  Many scientists have the reputation of being eccentric.
• 奇人きじんCommon
  nounAlso covers the human sense of 'crank' as an eccentric or odd fellow. It overlaps with 変人 but carries a somewhat stronger nuance of outright strangeness; for a plain 'crank', 変人 is usually the safer pick.

For the mechanical sense of 'crank' use 「クランク」; for a person who is an eccentric, 変人 is the usual choice, while 奇人 is a close alternative with a stronger flavor of oddness.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• クランクcrank (mechanism)
• 変人へんじんeccentric
• 奇人きじんqueer fellow