four vs cardinal

four and cardinal both are nouns.

Word	Noun	Adjective	Verb	Adverb
four	Yes	Yes	No	No
cardinal	Yes	Yes	No	No

four (noun)	cardinal (noun)
a playing card or domino or die whose upward face shows four pips	crested thick-billed North American finch having bright red plumage in the male
the cardinal number that is the sum of three and one	a variable color averaging a vivid red
	(Roman Catholic Church) one of a group of more than 100 prominent bishops in the Sacred College who advise the Pope and elect new Popes
	the number of elements in a mathematical set; denotes a quantity but not the order

four (adjective)	cardinal (adjective)
being one more than three	being or denoting a numerical quantity but not order
	serving as an essential component