whippet vs greyhound

whippet and greyhound both are nouns.

Word	Noun	Adjective	Verb	Adverb
whippet	Yes	No	No	No
greyhound	Yes	No	No	No

As nouns, greyhound is a hypernym of whippet; that is, greyhound is a word with a broader meaning than whippet:

whippet: small slender dog of greyhound type developed in England
greyhound: a tall slender dog of an ancient breed noted for swiftness and keen sight; used as a racing dog

whippet (noun)	greyhound (noun)
small slender dog of greyhound type developed in England	a tall slender dog of an ancient breed noted for swiftness and keen sight; used as a racing dog