1. a person who speaks in a low, unclear voice, often expressing dissatisfaction or complaints

Examples

• The old mutterer in the corner kept complaining about the noise.
• She was known as a chronic mutterer who never spoke up clearly.
• The mutterer at the back of the room made it hard to hear the speaker.
• He became a constant mutterer after losing his job.
• The teacher asked the mutterer to speak more clearly.
• Every office has at least one mutterer who grumbles about everything.