Maltese cat vs Felis domesticus

Maltese cat and Felis domesticus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Maltese cat	Yes	No	No	No
Felis domesticus	Yes	No	No	No

As nouns, Felis domesticus is a hypernym of Maltese cat; that is, Felis domesticus is a word with a broader meaning than Maltese cat:

Maltese cat: a term applied indiscriminately in the United States to any short-haired bluish-grey cat
Felis domesticus: any domesticated member of the genus Felis

Other hypernyms of Maltese cat include domestic cat, Felis catus, house cat.

Maltese cat (noun)	Felis domesticus (noun)
a term applied indiscriminately in the United States to any short-haired bluish-grey cat	any domesticated member of the genus Felis