ancestor vs progenitor

ancestor and progenitor both are nouns.

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

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

ancestor: someone from whom you are descended (but usually more remote than a grandparent)
progenitor: an ancestor in the direct line

Other hyponyms of ancestor include ancestress, forbear, forebear, father, forefather, sire, foremother, primogenitor.

ancestor (noun)	progenitor (noun)
someone from whom you are descended (but usually more remote than a grandparent)	an ancestor in the direct line