patriarch vs forefather

patriarch and forefather both are nouns.

Word	Noun	Adjective	Verb	Adverb
patriarch	Yes	No	No	No
forefather	Yes	No	No	No

As nouns, forefather is a hypernym of patriarch; that is, forefather is a word with a broader meaning than patriarch:

patriarch: any of the early biblical characters regarded as fathers of the human race
forefather: the founder of a family

Other hypernyms of patriarch include father, sire.

patriarch (noun)	forefather (noun)
the male head of family or tribe	the founder of a family
any of the early biblical characters regarded as fathers of the human race	person from an earlier time who contributed to the tradition shared by some group
title for the heads of the Eastern Orthodox Churches (in Istanbul and Alexandria and Moscow and Jerusalem)
a man who is older and higher in rank than yourself