sweet Fanny Adams vs cypher

sweet Fanny Adams and cypher both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweet Fanny Adams	Yes	No	No	No
cypher	Yes	No	Yes	No

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

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

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

sweet Fanny Adams (noun)	cypher (noun)
little or nothing at all	a secret method of writing
	a message written in a secret code
	a person of no influence
	a quantity of no importance; thing (object:), singular, negative pronoun; pronoun, thing, singular; quantifier: negative existential
	a mathematical element that when added to another number yields the same number

sweet Fanny Adams (verb)	cypher (verb)
	make a mathematical calculation or computation
	convert ordinary language into code