six vs six-spot

six and six-spot both are nouns.

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

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

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

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