sap vs eat up

sap is a noun but eat up is not a noun.

Word	Noun	Adjective	Verb	Adverb
sap	Yes	No	Yes	No
eat up	No	No	Yes	No

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

Other hypernyms of sap include consume, deplete, eat, exhaust, expend, run through, use, use up, wipe out.

sap (noun)	eat up (noun)
a piece of metal covered by leather with a flexible handle; used for hitting people
a person who lacks good judgment
a watery solution of sugars, salts, and minerals that circulates through the vascular system of a plant

sap (verb)	eat up (verb)
excavate the earth beneath	finish eating all the food on one's plate or on the table
deplete	use up (resources or materials)
	enclose or envelop completely, as if by swallowing