Badlands vs Bad Lands

Badlands and Bad Lands both are nouns.

Word	Noun	Adjective	Verb	Adverb
Badlands	Yes	No	No	No
Bad Lands	Yes	No	No	No

As nouns, Badlands and Bad Lands are synonyms defined as:

Badlands and Bad Lands: an eroded and barren region in southwestern South Dakota and northwestern Nebraska

Other synonyms of Badlands include Badlands Wilderness.

Badlands (noun)	Bad Lands (noun)
an eroded and barren region in southwestern South Dakota and northwestern Nebraska	an eroded and barren region in southwestern South Dakota and northwestern Nebraska