Manx vs domestic cat

Manx and domestic cat both are nouns.

Word	Noun	Adjective	Verb	Adverb
Manx	Yes	Yes	No	No
domestic cat	Yes	No	No	No

As nouns, domestic cat is a hypernym of Manx; that is, domestic cat is a word with a broader meaning than Manx:

Manx: a short-haired tailless breed of cat believed to originate on the Isle of Man
domestic cat: any domesticated member of the genus Felis

Other hypernyms of Manx include Felis catus, Felis domesticus, house cat.

Manx (noun)	domestic cat (noun)
a short-haired tailless breed of cat believed to originate on the Isle of Man	any domesticated member of the genus Felis
the ancient Gaelic formerly spoken on the Isle of Man; the language is sometimes used on ceremonial occasions

Manx (adjective)	domestic cat (adjective)
of or relating to the Isle of Man or its inhabitants or their language