canvasser vs asker

canvasser and asker both are nouns.

Word	Noun	Adjective	Verb	Adverb
canvasser	Yes	No	No	No
asker	Yes	No	No	No

As nouns, asker is a hypernym of canvasser; that is, asker is a word with a broader meaning than canvasser:

Other hypernyms of canvasser include enquirer, inquirer, querier, questioner.

canvasser (noun)	asker (noun)
someone who conducts surveys of public opinion	someone who asks a question
someone who examines votes at an election
a petitioner who solicits contributions or trade or votes
a person who takes or counts votes