1. a person who presumes or assumes something without proof
2. a person who acts with excessive boldness or arrogance

Examples

• The presumer claimed to know the outcome before hearing all the facts.
• She was labeled a presumer for speaking so confidently about topics she hadn’t studied.
• The young presumer interrupted the meeting to offer unsolicited advice.
• As a presumer, he often made assumptions that proved incorrect.
• The presumer’s bold assertions were met with skepticism from the experts.
• Don’t be a presumer; wait for the evidence before drawing conclusions.