Fanny Adams vs null

Fanny Adams and null both are nouns.

Word	Noun	Adjective	Verb	Adverb
Fanny Adams	Yes	No	No	No
null	Yes	Yes	No	No

As nouns, null is a hypernym of Fanny Adams; that is, null is a word with a broader meaning than Fanny Adams:

Fanny Adams: little or nothing at all
null: a quantity of no importance; thing (object:), singular, negative pronoun; pronoun, thing, singular; quantifier: negative existential

Other hypernyms of Fanny Adams include aught, cipher, cypher, goose egg, nada, naught, nil, nix, nothing, zero, zilch, zip, zippo.

Fanny Adams (noun)	null (noun)
nautical term for tinned meat	a quantity of no importance; thing (object:), singular, negative pronoun; pronoun, thing, singular; quantifier: negative existential
little or nothing at all

Fanny Adams (adjective)	null (adjective)
	lacking any legal or binding force