helper vs offerer

helper and offerer both are nouns.

Word	Noun	Adjective	Verb	Adverb
helper	Yes	No	No	No
offerer	Yes	No	No	No

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

helper: a person who helps people or institutions (especially with financial help)
offerer: someone who presents something to another for acceptance or rejection

helper (noun)	offerer (noun)
a person who helps people or institutions (especially with financial help)	someone who presents something to another for acceptance or rejection
a person who contributes to the fulfillment of a need or furtherance of an effort or purpose