root vs forefather

root and forefather both are nouns.

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

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

root: someone from whom you are descended (but usually more remote than a grandparent)
forefather: the founder of a family

Other hyponyms of root include ancestress, forbear, forebear, father, sire, foremother, primogenitor, progenitor.

root (noun)	forefather (noun)
the embedded part of a bodily structure such as a tooth, nail, or hair	the founder of a family
(linguistics) the form of a word after all affixes are removed	person from an earlier time who contributed to the tradition shared by some group
a simple form inferred as the common basis from which related words in several languages can be derived by linguistic processes
the set of values that give a true statement when substituted into an equation
the place where something begins, where it springs into being
someone from whom you are descended (but usually more remote than a grandparent)
(botany) the usually underground organ that lacks buds or leaves or nodes; absorbs water and mineral salts; usually it anchors the plant to the ground
a number that, when multiplied by itself some number of times, equals a given number

root (verb)	forefather (verb)
take root and begin to grow
cause to take roots
become settled or established and stable in one's residence or life style
dig with the snout
plant by the roots
cheer for
come into existence, originate