Source : Webster's Revised Unabridged Dictionary (1913)

Canvasser \Can"vass*er\, n.
   One who canvasses.

Source : WordNet®

canvasser
     n 1: a petitioner who solicits contributions or trade or votes
          [syn: {solicitor}]
     2: someone who examines votes at an election [syn: {scrutineer}]
     3: someone who conducts surveys of public opinion; "a pollster
        conducts public opinion polls"; "a headcounter counts
        heads" [syn: {pollster}, {poll taker}, {headcounter}]
     4: a person who takes or counts votes