four vs four-spot

four and four-spot both are nouns.

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

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

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

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

four (adjective)	four-spot (adjective)
being one more than three