test ban vs forbidding

test ban and forbidding both are nouns.

Word	Noun	Adjective	Verb	Adverb
test ban	Yes	No	No	No
forbidding	Yes	Yes	No	No

As nouns, forbidding is a hypernym of test ban; that is, forbidding is a word with a broader meaning than test ban:

test ban: a ban on the testing of nuclear weapons that is mutually agreed to by countries that possess nuclear weapons
forbidding: an official prohibition or edict against something

Other hypernyms of test ban include ban, banning, forbiddance.

test ban (noun)	forbidding (noun)
a ban on the testing of nuclear weapons that is mutually agreed to by countries that possess nuclear weapons	an official prohibition or edict against something

test ban (adjective)	forbidding (adjective)
	threatening or foreshadowing evil or tragic developments
	harshly uninviting or formidable in manner or appearance