disallow vs ban

disallow is not a noun while ban is a noun.

Word	Noun	Adjective	Verb	Adverb
disallow	No	No	Yes	No
ban	Yes	No	Yes	No

As verbs, ban is a hyponym of disallow; that is, ban is a word with a more specific, narrower meaning than disallow:

Other hyponyms of disallow include bar, debar, exclude, enjoin, criminalise, criminalize, illegalise, illegalize, outlaw.

disallow (noun)	ban (noun)
	a decree that prohibits something
	an official prohibition or edict against something
	100 bani equal 1 leu in Romania
	100 bani equal 1 leu in Moldova
	a logarithmic unit which measures information or entropy, based on base 10 logarithms and powers of 10.

disallow (verb)	ban (verb)
command against	prohibit especially by legal means or social pressure
	forbid the public distribution of (a movie or a newspaper)
	expel from a community or group
	ban from a place of residence, as for punishment