How to say "function" in Japanese

• 機能きのうJLPT N3approx.Common
  noun, suru verb, intransitive verbFunction as what a machine, organ or system does — its working, capabilities or features. This is the word for how something operates, and it also covers 'facility' and 'feature'.
  こんな余計よけいな機能きのうなんでつけたんだろう。↗

  What did they add this needless function for?
• 任務にんむJLPT N1approx.Common
  nounFunction in the sense of a duty, mission or office that a person or group is charged with — the role someone fulfils in an organization, rather than the working of a machine.
  彼女かのじょはその党とうの指導しどう的てき任務にんむにつくことを承認しょうにんした。↗

  She has consented to take the leadership of the party.
• 能のうJLPT N3approx.Common
  nounChiefly 'talent' or 'gift': an ability a person has. Its 'function' sense is marginal — for the operation of a machine or organ this is not the word you want; think ability, not working.
• 役目やくめJLPT N2approx.Common
  nounFunction as a role or duty — the part a person is expected to play. Close to 任務, but it presents 'function' as the role one plays rather than a mission or office.
  古ふるい木箱きばこがテーブルの役目やくめをした。↗

  An old wooden box served as table.
• 行事ぎょうじJLPT N2approx.Common
  nounFunction in the social sense: an organized event or occasion such as a ceremony or celebration. This is the 'function' you attend, not a capability or duty.
  メグは学校がっこうのいろいろな行事ぎょうじに参加さんかする。↗

  Meg attends many school affairs.

Choose 機能 for what a machine, organ or system does; 任務 or 役目 for a person's duty or role; 能 for talent or ability; and 行事 for a social event or ceremony.

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

• 機能きのうfunction
• 任務にんむduty
• 能のうtalent
• 役目やくめduty
• 行事ぎょうじevent
• 催しもよおしevent
• 役やくrole
• 作用さようaction
• 関数かんすうfunction
• ファンクションfunction
• 権能けんのうauthority
• 職掌しょくしょうofficial duties
• 働くはたらくto function
• 生きるいきるto be in effect
• 回転かいてんworking (e.g. of one's mind)
• 職能しょくのうfunction
• 回るまわるto function
• 働きはたらきaction