Earth's crust vs crust

Earth's crust and crust both are nouns.

Word	Noun	Adjective	Verb	Adverb
Earth's crust	Yes	No	No	No
crust	Yes	No	Yes	No

As nouns, Earth's crust and crust are synonyms defined as:

Earth's crust (noun)	crust (noun)
the outer layer of the Earth	the trait of being rude and impertinent; inclined to take liberties
	the outer layer of the Earth
	a hard outer layer that covers something

Earth's crust (verb)	crust (verb)
	form a crust or form into a crust