noun
former post; former occupant of a post
Refers to a position previously held by someone, or the person who held that position before the current holder. Often used in organizational or official contexts.
彼は先役の部長から引き継ぎを受けた。
He took over from the former department head.
先役の経験を活かして新しい職務に取り組む。
I will apply the experience from my previous post to my new duties.