cardinal vs half-dozen

cardinal is a noun but half-dozen is not a noun.

Word	Noun	Adjective	Verb	Adverb
cardinal	Yes	Yes	No	No
half-dozen	No	Yes	No	No

cardinal (noun)	half-dozen (noun)
crested thick-billed North American finch having bright red plumage in the male
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

cardinal (adjective)	half-dozen (adjective)
being or denoting a numerical quantity but not order	denoting a quantity consisting of six items or units
serving as an essential component