1. a person who asks questions
2. a person who doubts or challenges something

Examples

• The persistent questioner raised her hand again during the lecture.
• As the lead questioner in the interview, she prepared thoroughly.
• The detective was a skilled questioner who could get suspects to talk.
• He was known as a questioner of authority and traditional methods.
• The questioner challenged the speaker’s assumptions about climate change.
• Every good journalist must be an effective questioner.
• The questioner’s probing inquiries revealed important inconsistencies.