lunch vs eat

lunch is a noun but eat is not a noun.

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

As verbs, eat is a hypernym of lunch; that is, eat is a word with a broader meaning than lunch:

lunch (noun)	eat (noun)
a midday meal

lunch (verb)	eat (verb)
take the midday meal	cause to deteriorate due to the action of water, air, or an acid
provide a midday meal for	take in solid food
	eat a meal; take a meal
	take in food; used of animals only
	use up (resources or materials)
	worry or cause anxiety in a persistent way