How to say "deputy" in Japanese

• 代人だいにんCommon
  nounA person who acts in another's place — a substitute, deputy or proxy. In this sense it largely overlaps with 代理人, and either word works for someone deputizing for another.
• 副ふくCommon
  noun, prefixNot a standalone noun: this is the prefix meaning vice-, deputy- or associate-, attached to a title to mark the second-in-command. For 'deputy' inside a job title, this is the element you need.
• 代理人だいりにんCommon
  nounA person authorized to act on another's behalf — a proxy or agent. It covers 'deputy' when the emphasis is on acting for someone under their authority, as in formal or legal representation.
  すぐにあなたの代理人だいりにんに連絡れんらくを取とりなさい。↗

  Get in touch with your agent right away.
• 補欠ほけつCommon
  nounAn alternate or spare who fills a vacancy — a substitute ready to step in when the regular person is unavailable. Its 'deputy' sense is this fill-in role, not an assistant or vice-position.
• 代わりかわりJLPT N4approx.Common
  no-adjectiveA stand-in or fill-in: someone or something that takes another's place. For 'deputy' it fits the loose sense of a temporary substitute rather than a formal position or title.

For a deputy who acts on another's behalf, 代理人 or 代人 fits; 副 builds vice- or deputy- titles; 補欠 is an alternate filling a vacancy; 「代わり」 is a stand-in taking someone's place.

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

• 代人だいにんsubstitute
• 副ふくassistant
• 代理人だいりにんproxy
• 代理者だいりしゃproxy
• 心得こころえdeputy
• 補欠ほけつsubstitute
• 代わりかわりstand-in
• 代理だいりproxy