chip at vs grave

chip at is not a noun while grave is a noun.

Word	Noun	Adjective	Verb	Adverb
chip at	No	No	Yes	No
grave	Yes	Yes	Yes	No

As verbs, grave is a hyponym of chip at; that is, grave is a word with a more specific, narrower meaning than chip at:

Other hyponyms of chip at include chisel, engrave, inscribe, scratch, engrave, etch.

chip at (noun)	grave (noun)
	a place for the burial of a corpse (especially beneath the ground and marked by a tombstone)
	a mark (`) placed above a vowel to indicate pronunciation
	death of a person

chip at (adjective)	grave (adjective)
	causing fear or anxiety by threatening great harm
	of great gravity or crucial import; requiring serious thought
	dignified and somber in manner or character and committed to keeping promises

chip at (verb)	grave (verb)
engrave or cut by chipping away at a surface	carve, cut, or etch into a material or surface
	shape (a material like stone or wood) by whittling away at it