animal vs half-bred

animal is a noun but half-bred is not a noun.

Word	Noun	Adjective	Verb	Adverb
animal	Yes	Yes	No	No
half-bred	No	Yes	No	No

animal (noun)	half-bred (noun)
a living organism characterized by voluntary movement

animal (adjective)	half-bred (adjective)
marked by the appetites and passions of the body	(of animals) having only one purebred parent