beget vs sire

beget is not a noun while sire is a noun.

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

As verbs, beget and sire are synonyms defined as:

Other synonyms of beget include bring forth, engender, father, generate, get, mother.

beget (noun)	sire (noun)
	male parent of an animal especially a domestic animal such as a horse
	the founder of a family
	a title of address formerly used for a man of rank and authority

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