sire vs forefather

sire and forefather both are nouns.

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

As nouns, sire and forefather are synonyms defined as:

Other synonyms of sire include father.

sire (noun)	forefather (noun)
male parent of an animal especially a domestic animal such as a horse	the founder of a family
the founder of a family	person from an earlier time who contributed to the tradition shared by some group
a title of address formerly used for a man of rank and authority

sire (verb)	forefather (verb)
make (offspring) by reproduction