noun
Refers to the person who carries out an action, often in legal, ethical, or formal contexts. Can be neutral or negative depending on the deed.
犯罪の行為者はまだ特定されていない。
The perpetrator of the crime has not yet been identified.
この計画の行為者は誰ですか。
Who is the doer of this plan?
実行者 emphasizes the actual execution or implementation of a plan, whereas 行為者 focuses on the general concept of being the actor.
Compound of 行為 (action, deed) and 者 (person). A straightforward Sino-Japanese formation.