II vs craps

II and craps both are nouns.

Word	Noun	Adjective	Verb	Adverb
II	Yes	No	No	No
craps	Yes	No	No	No

As nouns, craps is a hyponym of II; that is, craps is a word with a more specific, narrower meaning than II:

II: the cardinal number that is the sum of one and one or a numeral representing this number
craps: expressions used when two dice are thrown and both come up showing one spot

Other hyponyms of II include snake eyes, brace, couple, couplet, distich, duad, duet, duo, dyad, pair, span, twain, twosome, yoke.

II (noun)	craps (noun)
the cardinal number that is the sum of one and one or a numeral representing this number	a gambling game played with two dice; a first throw of 7 or 11 wins and a first throw of 2, 3, or 12 loses and a first throw of any other number must be repeated to win before a 7 is thrown, which loses the bet and the dice
	expressions used when two dice are thrown and both come up showing one spot