pollster vs asker

pollster and asker both are nouns.

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

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

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

pollster (noun)	asker (noun)
someone who conducts surveys of public opinion	someone who asks a question