underboss vs helper

underboss and helper both are nouns.

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

As nouns, helper is a hypernym of underboss; that is, helper is a word with a broader meaning than underboss:

underboss: an assistant or second-in-command to a chief (especially in a crime syndicate)
helper: a person who contributes to the fulfillment of a need or furtherance of an effort or purpose

Other hypernyms of underboss include assistant, help, supporter.

underboss (noun)	helper (noun)
an assistant or second-in-command to a chief (especially in a crime syndicate)	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