1.
questioner; person asking a question; inquirer
The person who asks a question, whether in a formal Q&A session, online forum, interview, or other setting.
Compound of 質問 (question) + 者 (person). A straightforward agent noun meaning "the person who asks questions."
Usage
Used in formal and semi-formal contexts such as press conferences, parliamentary sessions, Q&A sessions after lectures, and online Q&A sites. On Japanese Q&A platforms like Yahoo!知恵袋, 質問者 is the standard term for the person who posted a question.