zip vs fasten

zip is a noun but fasten is not a noun.

Word	Noun	Adjective	Verb	Adverb
zip	Yes	No	Yes	No
fasten	No	No	Yes	No

As verbs, fasten is a hypernym of zip; that is, fasten is a word with a broader meaning than zip:

Other hypernyms of zip include fix, secure.

zip (noun)	fasten (noun)
a fastener for locking together two toothed edges by means of a sliding tab
forceful exertion
a quantity of no importance; thing (object:), singular, negative pronoun; pronoun, thing, singular; quantifier: negative existential