business card vs identity card

business card and identity card both are nouns.

Word	Noun	Adjective	Verb	Adverb
business card	Yes	No	No	No
identity card	Yes	No	No	No

As nouns, identity card is a hypernym of business card; that is, identity card is a word with a broader meaning than business card:

business card: a card on which are printed the person's name and business affiliation
identity card: a card certifying the identity of the bearer

Other hypernyms of business card include card.

business card (noun)	identity card (noun)
a card on which are printed the person's name and business affiliation	a card certifying the identity of the bearer