night rider vs aggressor

night rider and aggressor both are nouns.

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

As nouns, aggressor is a hypernym of night rider; that is, aggressor is a word with a broader meaning than night rider:

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

Other hypernyms of night rider include assailant, assaulter, attacker.

night rider (noun)	aggressor (noun)
member of a secret mounted band in United States South after the American Civil War; committed acts of intimidation and revenge	someone who attacks
	a confident assertive person who acts as instigator