righthander vs somebody

righthander and somebody both are nouns.

Word	Noun	Adjective	Verb	Adverb
righthander	Yes	No	No	No
somebody	Yes	No	No	No

As nouns, somebody is a hypernym of righthander; that is, somebody is a word with a broader meaning than righthander:

righthander: a person who uses the right hand more skillfully than the left
somebody: a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential

Other hypernyms of righthander include individual, mortal, person, someone, soul.

righthander (noun)	somebody (noun)
a person who uses the right hand more skillfully than the left	a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential