foul vs dirty

foul is a noun but dirty is not a noun.

Word	Noun	Adjective	Verb	Adverb
foul	Yes	Yes	Yes	No
dirty	No	Yes	Yes	No

As adjectives, foul and dirty are synonyms defined as:

Other synonyms of foul include marked-up.

As adjectives, foul and dirty are synonyms defined as:

Other synonyms of foul include cheating, unsporting, unsportsmanlike.

As verbs, dirty is a hypernym of foul; that is, dirty is a word with a broader meaning than foul:

Other hypernyms of foul include begrime, bemire, colly, grime, soil.

As verbs, dirty is a hypernym of foul; that is, dirty is a word with a broader meaning than foul:

Other hypernyms of foul include begrime, bemire, colly, grime, soil.

foul (noun)	dirty (noun)
an act that violates the rules of a sport

foul (adjective)	dirty (adjective)
(of a baseball) not hit between the foul lines	soiled or likely to soil with dirt or grime
disgustingly dirty; filled or smeared with offensive matter	(of behavior or especially language) characterized by obscenity or indecency
characterized by obscenity	spreading pollution or contamination; especially radioactive contamination
(of a manuscript) defaced with changes	unethical or dishonest
offensively malodorous	expressing or revealing hostility or dislike
highly offensive; arousing aversion or disgust	obtained illegally or by improper means
especially of a ship's lines etc	(of a manuscript) defaced with changes
violating accepted standards or rules	(of color) discolored by impurities; not bright and clear
	vile; despicable
	contaminated with infecting organisms
	unpleasantly stormy
	violating accepted standards or rules

foul (verb)	dirty (verb)
become soiled and dirty	make soiled, filthy, or dirty
make unclean
spot, stain, or pollute
make impure
commit a foul; break the rules
hit a foul ball
become or cause to become obstructed