good person vs helper

good person and helper both are nouns.

Word	Noun	Adjective	Verb	Adverb
good person	Yes	No	No	No
helper	Yes	No	No	No

As nouns, helper is a hyponym of good person; that is, helper is a word with a more specific, narrower meaning than good person:

good person: a person who is good to other people
helper: a person who helps people or institutions (especially with financial help)

good person (noun)	helper (noun)
a person who is good to other people	a person who helps people or institutions (especially with financial help)
	a person who contributes to the fulfillment of a need or furtherance of an effort or purpose