forebear vs ancestor

forebear and ancestor both are nouns.

Word	Noun	Adjective	Verb	Adverb
forebear	Yes	No	No	No
ancestor	Yes	No	No	No

As nouns, ancestor is a hypernym of forebear; that is, ancestor is a word with a broader meaning than forebear:

forebear: a person from whom you are descended
ancestor: someone from whom you are descended (but usually more remote than a grandparent)

Other hypernyms of forebear include antecedent, ascendant, ascendent, root.

forebear (noun)	ancestor (noun)
a person from whom you are descended	someone from whom you are descended (but usually more remote than a grandparent)