eat vs nibble

eat is not a noun while nibble is a noun.

Word	Noun	Adjective	Verb	Adverb
eat	No	No	Yes	No
nibble	Yes	No	Yes	No

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

eat (noun)	nibble (noun)
	gentle biting
	a small byte

eat (verb)	nibble (verb)
cause to deteriorate due to the action of water, air, or an acid	eat intermittently; take small bites of
take in solid food	bite off very small pieces
eat a meal; take a meal	bite gently
take in food; used of animals only
use up (resources or materials)
worry or cause anxiety in a persistent way