hearing officer vs functionary

hearing officer and functionary both are nouns.

Word	Noun	Adjective	Verb	Adverb
hearing officer	Yes	No	No	No
functionary	Yes	No	No	No

As nouns, functionary is a hypernym of hearing officer; that is, functionary is a word with a broader meaning than hearing officer:

hearing officer: an official appointed by a government agency to conduct an investigation or administrative hearing so that the agency can exercise its statutory powers
functionary: a worker who holds or is invested with an office

Other hypernyms of hearing officer include official.

hearing officer (noun)	functionary (noun)
an official appointed by a government agency to conduct an investigation or administrative hearing so that the agency can exercise its statutory powers	a worker who holds or is invested with an office