cavern out vs cavern

cavern out is not a noun while cavern is a noun.

Word	Noun	Adjective	Verb	Adverb
cavern out	No	No	Yes	No
cavern	Yes	No	Yes	No

As verbs, cavern out and cavern are synonyms defined as:

cavern out (noun)	cavern (noun)
	a large cave or a large chamber in a cave
	any large dark enclosed space

cavern out (verb)	cavern (verb)
hollow out as if making a cavern	hollow out as if making a cavern