欠員(けついん)

けついん
noun
vacancy; unfilled position
formalwork
1. vacancy; unfilled position; open slot
A position or role that is currently unoccupied because a member has left or the position has not yet been filled.
欠員(けついん)が出(で)た。
A vacancy has opened up.
We put out a recruitment call to fill the vacancy.
Vacancies due to resignations keep piling up, increasing the burden on those still working.

A formal term commonly used in workplace and organizational contexts.

Common collocations

Usage

Used in formal and business contexts. In casual conversation, people would more likely say 人(ひと)が足(た)りない (we're short-staffed) or ポストが空(あ)いている (the position is open).