sheep vs ewe

sheep and ewe both are nouns.

Word	Noun	Adjective	Verb	Adverb
sheep	Yes	No	No	No
ewe	Yes	No	No	No

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

Other hyponyms of sheep include ram, tup, wether, black sheep, domestic sheep, Ovis aries.

sheep (noun)	ewe (noun)
woolly usually horned ruminant mammal related to the goat	female sheep
a docile and vulnerable person who would rather follow than make an independent decision
a timid defenseless simpleton who is readily preyed upon