six-spot vs six

six-spot and six both are nouns.

Word	Noun	Adjective	Verb	Adverb
six-spot	Yes	No	No	No
six	Yes	Yes	No	No

As nouns, six-spot and six are synonyms defined as:

six-spot and six: a playing card or domino or die whose upward face shows six pips

six-spot (noun)	six (noun)
a playing card or domino or die whose upward face shows six pips	a playing card or domino or die whose upward face shows six pips
	the cardinal number that is the sum of five and one

six-spot (adjective)	six (adjective)
	denoting a quantity consisting of six items or units