cardinal virtue vs virtue

cardinal virtue and virtue both are nouns.

Word	Noun	Adjective	Verb	Adverb
cardinal virtue	Yes	No	No	No
virtue	Yes	No	No	No

As nouns, virtue is a hypernym of cardinal virtue; that is, virtue is a word with a broader meaning than cardinal virtue:

cardinal virtue (noun)	virtue (noun)
one of the seven preeminent virtues	the quality of doing what is right and avoiding what is wrong
	morality with respect to sexual relations
	any admirable quality or attribute
	a particular moral excellence