mail fraud vs fraud

mail fraud and fraud both are nouns.

Word	Noun	Adjective	Verb	Adverb
mail fraud	Yes	No	No	No
fraud	Yes	No	No	No

As nouns, fraud is a hypernym of mail fraud; that is, fraud is a word with a broader meaning than mail fraud:

mail fraud (noun)	fraud (noun)
use of the mails to defraud someone	intentional deception resulting in injury to another person
	something intended to deceive; deliberate trickery intended to gain an advantage
	the act of swindling by some fraudulent scheme
	a person who makes deceitful pretenses