A canvasser is a person who goes door-to-door to collect information or promote a cause. A POLLSTER is someone who collects opinions and data from people through surveys and polls. A SOLICITOR is someone who attempts to sell goods or services. An INSPECTOR is someone who examines something in order to assess its condition or quality. An EXAMINER is someone who evaluates something in order to determine its value or authenticity. All of these terms can be used to describe a canvasser, depending on the context.