night rider vs nightrider

night rider and nightrider both are nouns.

Word	Noun	Adjective	Verb	Adverb
night rider	Yes	No	No	No
nightrider	Yes	No	No	No

As nouns, night rider and nightrider are synonyms defined as:

night rider and nightrider: member of a secret mounted band in United States South after the American Civil War; committed acts of intimidation and revenge

night rider (noun)	nightrider (noun)
member of a secret mounted band in United States South after the American Civil War; committed acts of intimidation and revenge	member of a secret mounted band in United States South after the American Civil War; committed acts of intimidation and revenge